Helping the Snow Gods: #CloudSeeding Grows as Weapon Against #GlobalWarming — Inside Climate News

From Inside Climate News (Bob Berwyn):

New research supports seeding efforts to bolster water supplies in drying regions, but some scientists question its effectiveness in addressing climate change.

Winter bonfires paying homage to snow gods have long been a tradition in cold weather regions around the world.

But in the last 70 years or so, communities in the western United States have gone beyond rituals and added a technological twist. Across hundreds of mountaintops, from the Sierra Nevada to the Sawtooths, Wasatch and Colorado Front Range, cloud seeding experts are now often burning small amounts of silver iodide with the aim of bolstering dwindling water supplies.

The vaporized metal particles are ideal kernels for new ice crystals. When moist, super-cooled air rises over mountain ranges under predictable winds, it sets up perfect conditions for the crystalline alchemy that creates snow, the white gold craved by ski resorts, ranchers and farmers and even distant cities that need mountain water to survive.

The scramble for water has intensified as global warming has battered much of the West during the last 20 years with heat waves, droughts and wildfires. With projections for declining snowpack and river flows, cloud seeding is becoming a regional climate adaptation measure costing several million dollars each year. In other regions, including parts of the central United States, seeding has also been used to try and enhance summer rains and to reduce the risk of severe hail storms.

Still Controversial

But even as governments and businesses increase the practice, questions remain about how effective it is, and some leading climate scientists say it should not be seen as a meaningful response to climate change. Though cloud seeding has expanded to cover tens of thousands of square miles across the West, there are no recent comprehensive studies assessing the effects in both targeted and non-targeted areas. Cloud-seeding permits are issued under a patchwork of state and federal rules, which sometimes cuts the public out of the process.

Several panels at a recent conference on weather modification addressed some of those issues, and included presentations on how efforts to cooperate on regional cloud seeding projects could serve as a model for governance of even larger scale climate-mitigating geoengineering projects.

Cloud Seeding targets North America. Map credit: North American Weather Modification Council

Some elected officials and water experts say the money is well spent because it produces millions of gallons of water that can be stored and used during drier and hotter summers, when stream flows dwindle. Scientific studies in the last few years show that cloud seeding works during suitable weather patterns that are already conducive to snowfall.

In the winter of 2018-2019, water managers in Colorado said their central mountains cloud seeding program produced between 80,000 and 90,000 acre feet of water at a cost of $2.70 per acre foot—a bargain in a region where prices per acre foot can reach $30,000. An acre foot of water is 325,851 gallons, enough for two average Colorado families for a year…

Research in the last two decades proves that the physical process works, but it’s still not clear how much water it produces. At best, the latest studies “hold promise for narrowing the uncertainty” that has accompanied such research over its long history, the paper concluded.

Altering clouds with plumes of metallic smoke might work on a localized basis, but it isn’t the right solution for large-scale and long-term regional drying and warming, said atmospheric scientist Kevin Trenberth, with the National Center for Atmospheric Research and the University of Auckland, in New Zealand.

Facing a drier future, water managers turn to science — The Rio Blanco Herald-Times #ColoradoRiver #COriver #aridification

A flight from NASA’s Airborne Snow Observatory gathers data about the snowpack above the reservoir on a June 24 flight. Information gathered from the flight helped Denver Water manage reservoir operations. Photo courtesy of Quantum Spatial

From the Colorado River District via The Rio Blanco Herald-Times:

A growing body of research shows that the Upper Colorado River Basin is growing warmer on average. In fact, the national hot spot centers on Western Colorado and much of the Southwest.

A result: a significant reduction in the snowpack that makes up the Southwest’s main water supply.

In the Colorado River District’s “Know Your Snow” webinar, Deputy Chief Engineer Dave Kanzer and National Snow and Ice Data Center researcher Jeff Deems explored how water managers and snow scientists are studying and adapting to the changes to our snowpack and water supply.

The “Know Your Snow” webinar is available online at http://www.coloradoriverdistrict.org/events-directory/webinars/ (scan the Zapcode on the photo to the right with your Zappar smartphone app for a direct link.)

About three-quarters of the snowmelt that forms the Colorado River’s flow falls as snow at elevations above 8,500 feet in the mountains of the Upper Colorado Basin, Kanzer explained. Deems pointed out that the 15 Western Slope counties that make up the Colorado River District have warmed at a rate from about 2 degrees Fahrenheit in Summit County to more than 4 degrees in Mesa, Montrose, Ouray and Rio Blanco counties since about the early 1900s, according to data developed by the National Oceanic and Atmospheric Administration.

“We’re seeing changes on the order of 4 or 5 degrees in parts of the District,” Deems said. “This is just a slice out of this big, warming bullseye that is hitting the Upper Colorado (River) Basin over that time period. This is a problem for us because we rely on the snowpack, and that’s because warming reduces stream flow through a number of different mechanisms in this snowmelt-dominated basin.”

That reduction comes from several factors: more snow falling as rain, earlier spring snowmelt, more snow directly evaporating into the atmosphere instead of melting into streams and a longer growing season that has plants taking up more water.

Deems explained that for every 1 degree of warming, there is an estimated 3 to 4% decline in annual runoff. That’s about double the amount of water Las Vegas uses in one year, and 18 months of water supply for the city of Los Angeles, Deems said.

A recent study by the U.S. Geological Survey found that a decline in flow due to warming is even greater than earlier studies have shown, with statistics suggesting that average annual flow decreases by 9.3% for every 1.8 degrees of warming.

All of this poses a threat to drinking water, irrigation to grow our food and water to maintain healthy wildlife habitats. The Colorado River District is not only studying the water-supply risks posed by warming temperatures but also implementing solutions such as cloud seeding to make sure West Slope communities are prepared for future challenges.

Cloud-seeding graphic via Science Matters

Cloud seeding to increase snowpack

As part of an effort to boost snowpack, Kanzer coordinates the Colorado River District’s cloud seeding program. Increasingly, water managers are turning to cloud seeding, a practice that can increase how much snow winter storms produce.

“We’re trying to figure out how to mitigate and adapt to a changing world,” Kanzer said. “We’re doing this through cloud seeding, and (we’re) implementing these programs throughout Western Colorado. In fact, this is going on throughout the West and throughout the world.”

Cloud seeding requires a specific set of conditions to be successful, Kanzer explained. A cloud must contain super-cooled water. Water vapor in these clouds is cold enough to form ice crystals, around 5 to 23 degrees Fahrenheit, but it needs something on which to crystalize. When conditions in a storm system are right, with favorable winds with proper uplift, cloud seeding generators send tiny particles of silver iodide into the moisture-laden clouds, typically using propane-fired burners on the ground.

Silver iodide has been proven to be safe for the environment, Kanzer said, adding that it is effective because and it naturally has a similar crystal structure to the ice crystals that form snowflakes.

The super-cooled liquid water more efficiently freezes on to these introduced tiny particles of silver iodide, building small ice crystals that grow into snowflakes.

Kanzer said cloud seeding could increase snow on the ground by up to 15%, boosting what might have been a 10-inch snowstorm by 1.5 inches. After a successful season of cloud seeding, this might, in turn, lead to as much as a 5% increase in streamflow in watersheds where cloud seeding occurred. This increases recreation opportunities for skiers in the winter and boaters in the warmer months, he added.

“And it helps us with our water supplies, of course, and that’s what we’re really focused on here at the Colorado River District,” Kanzer said.

This map shows the snowpack depth of the Maroon Bells in spring 2019. The map was created with information from NASA’s Airborne Snow Observatory, which will help water managers make more accurate streamflow predictions. Jeffrey Deems/ASO, National Snow and Ice Data Center

Improving predictions with better data

While Kanzer’s work focuses on increasing the amount of snowpack, Deems’ research seeks to better understand what snow we have.

He explained that water supply forecasts are traditionally generated by comparing the current amount of snow on the ground at fixed locations to historical streamflow records. With the changes we are experiencing, Deems said these methods of comparing the present to the past are no longer accurate.

Additionally, snowpack is measured by a network of weather stations widely spread out across the mountain landscape where Colorado’s snowfall accumulates. While these stations provide accurate measurements in very specific locations, they don’t indicate how much snow, and how much water, might be stored high in the mountains, above the elevations where these stations are located.

Deems’ company, the Airborne Snow Observatory, uses a system called light detection and ranging — LIDAR for short — to measure snow across the entire landscape. From a plane, Deems’ team sends pulses of scanning laser light toward the earth, which reflect off the snow. Researchers can then use information in the reflection to build a three-dimensional picture of the snowscape.

This technology gives snow scientists and water planners landscape-based information about how much snow, and water, is present. This technology is detailed enough to reveal the deep pockets of snow below bare slopes where avalanches occurred or even areas where snowmaking was used to make terrain parks on a ski run.

This more comprehensive of the snowpack significantly improves water supply forecasts critical to water managers in making decisions.

Together with cloud seeding, this technology is helping water managers turn the corner from historical practices to prepare for and adapt to a changing world in the Upper Colorado River Basin.

For more information, visit ColoradoRiverDistrict.org. The “Know Your Snow” webinar is available online at http://www.coloradoriverdistrict.org/events-directory/webinars/.

Cloud seeding study validates ski industry staple — @AspenJournalism

Scenes from the Seeded and Natural Orographic Wintertime Clouds: The Idaho Experiment (SNOWIE) project, which was undertaken in Idaho’s Payette Basin in winter 2017. Credit: Joshua Aikins via Aspen Journalism

From Aspen Journalism (David O. Williams):

n innovative new study conducted in Idaho and published on Monday seems to confirm what Vail and other Colorado ski resorts have believed for decades — that “cloud seeding can boost snowfall across a wide area if the atmospheric conditions are favorable.”

“This is a revelation. We can definitely say that cloud seeding enhances snowfall under the right conditions,” said Sarah Tessendorf, a scientist at the National Center for Atmospheric Research in Boulder and co-author of a new paper on the research conducted by scientists from the University of Colorado Boulder and University of Wyoming, among others.

Cloud seeding uses ground-based generators to disperse dust-sized silver iodide particles into clouds so that ice crystals can form on those particles and fall to the ground in the form of snow. Scientists, water managers and ski industry executives say it’s precipitation that would otherwise stay in the clouds, so cloud seeding is an environmentally safe way to enhance snowfall.

But the efficiency of cloud seeding has so far been hard to prove. Tessendorf said previous cloud seeding studies were unable to achieve statistically significant results because the natural variability of the weather was too great and demanded a larger sample size than could be reasonably obtained, for financial reasons.

In winter 2017, the National Science Foundation, which sponsors NCAR, teamed up with the Idaho Power Company to conduct a field study called SNOWIE (Seeded and Natural Orographic Wintertime Clouds — the Idaho Experiment).

SNOWIE used supercomputing technology to develop a new computer model to simulate cloud seeding, as well as new measurement capabilities, such as a high-resolution cloud radar on a Wyoming research aircraft that can see previously invisible cloud features. Researchers also located mobile radars on mountain ridges north of Boise to see clouds not visible to stationary National Weather Service radars that are blocked by the mountains themselves.

The scientists then used airborne seeding instead of ground-based generators because the silver iodide dispersed downwind from the aircraft in a zig-zag pattern, which is a very unnatural pattern for precipitation to form.

That allowed the scientists “to unambiguously detect the impact of cloud seeding in these clouds using the mobile and airborne radars,” Tessendorf said. “This had never been done before. In the three cases we report on, there was negligible natural snow falling, so the zig-zag pattern was able to be detected very clearly and tracked to the ground to quantify the snow reaching the ground due to seeding.”

One of the examples cited in a press release accompanying the study was a cloud-seeding flight on Jan. 19, 2017, that generated snow for 67 minutes, dusting about 900 square miles with a tenth of a millimeter of snow beyond what was falling naturally.

“This was barely enough snow to cling to the researchers’ eyelashes,” the release reads, ‘but it would have stayed in the air if not for cloud seeding.”

“We tracked the seeding plume from the time we put it into the cloud until it generated snow that actually fell onto the ground,” said Katja Friedrich, a University of Colorado Boulder professor and lead author of the new study.

Scenes from the Seeded and Natural Orographic Wintertime Clouds: The Idaho Experiment (SNOWIE) project, which was undertaken in Idaho’s Payette Basin in winter 2017. Credit: Joshua Aikins via Aspen Journalism

Finding the ideal storms

Dave Kanzer, deputy chief engineer for the Colorado River District, helps oversee a system of 25 ground-based cloud-seeding generators in the central Colorado region that includes Grand, Summit, Eagle and parts of Pitkin County. Nearby generators include one atop Arrowhead and another above Camp Hale.

Kanzer said storms from the north and northwest, which tend to be colder, are ideal for cloud seeding, with temperatures in the clouds no higher than 21 degrees Fahrenheit and no lower than 5 degrees Fahrenheit. If the clouds have the right temperature range and the right moisture levels but lack sufficient particles for ice crystals to form, that’s where cloud seeding comes in.

“We take advantage of the first two and we add the proper amount of particulate matter to enhance the snowfall and precipitation … and that accumulates in the snowpack somewhere in the range of between 5 and 15% on a per storm basis when those conditions are met,” Kanzer said. “And that helps to increase the water yield of the snow sheds in the range of 1 to, 4% of water on a seasonal basis.”

Scenes from the Seeded and Natural Orographic Wintertime Clouds: The Idaho Experiment (SNOWIE) project, which was undertaken in Idaho’s Payette Basin in winter 2017. Credit: Joshua Aikins via Aspen Journalism

A tool to maintain snowpack

The Colorado Department of Natural Resources regulates cloud seeding, permitting operations in nine different parts of the state. The operations in the central zone, at the headwaters of the Colorado River, are funded by a wide range of groups, including Front Range utilities and water districts that divert Western Slope water, including Denver Water and Northern Water.

The Colorado River District spends around a $150,000 a year contracting with Western Weather Group to run the program, which Kanzer said is about the same amount Vail Resorts spends on the program for its four Colorado ski areas – Vail, Beaver Creek, Breckenridge and Keystone.

Vail Resorts declined to comment for this story.

Kanzer presented on cloud seeding at a November Eagle River Watershed Council meeting in Avon, where a few of the 50 or so participants got heated in their questioning of the environmental safety of the process.

Kanzer said cloud seeding is safe, using inert silver iodide that cannot be detected in the environment after it’s released into clouds. He added the process could become increasingly critical to maintaining mountain snowpack as the climate changes.

“It’s one tool that we can use to mitigate or adapt to the changes that we have not only predicted but are starting to experience with shorter snow-covered seasons,” Kanzer said. “And so (cloud seeding) helps us extend that time or at least forestall the reduction.”

Aspen Journalism collaborates with The Vail Daily and other Swift Communications newspapers on coverage of water and rivers. This story ran in the Feb. 25 edition of The Vail Daily.

Cloud-seeding graphic via Science Matters

Scientists demonstrate that #cloudseeding can generate snowfall — @NCAR_Science #snowpack #runoff

Here’s the release from NCAR/UCAR (David Hokansky):

Scientists announced today that they have successfully used a combination of radars and snow gauges to measure the impact of cloud seeding on snowfall. The new research addresses decades of speculation about the effectiveness of artificial methods to increase precipitation, demonstrating unambiguously that cloud seeding can boost snowfall across a wide area if the atmospheric conditions are favorable.

“This is a revelation,” said Sarah Tessendorf, a scientist at the National Center for Atmospheric Research (NCAR) and co-author of a new paper about the research. “We can definitely say that cloud seeding enhances snowfall under the right conditions.”

The researchers, including scientists from the University of Colorado Boulder, University of Wyoming, and University of Illinois at Urbana-Champaign, arrived at their results by analyzing detailed observations taken in a cloud seeding experiment in Idaho during the winter of 2017. They found that injecting clouds with silver iodide generated precipitation at multiple sites at the ground, sometimes creating snowfall where none had existed.

The study provides the most comprehensive evidence to date that cloud seeding can generate rain or snow.

Tessendorf cautioned, however, that successfully producing precipitation requires the presence of clouds. The results are also dependent on such atmospheric factors as local winds. Even when cloud seeding enhances precipitation, there are additional factors that will determine if it is a cost-effective approach to increasing snowpack or replenishing reservoirs.

“The seeding produces ice and that ice can form snow, but is it enough additional snow to make it cost effective?” she asked. “For water managers, the bottom line is the amount of snowpack that you’re building over the whole winter and how much runoff it will generate. We are looking into some promising approaches to address those bigger questions, but we still have plenty of work to do to get there.”

The study was published this week in Proceedings of the National Academy of Sciences. Funding came from the National Science Foundation (NSF), which is NCAR’s sponsor, and from the Idaho Power Company.

A scientific challenge

As far back as the 1940s, scientists demonstrated that injecting certain types of particles into clouds could induce ice to form and grow around them until they fell out of the clouds.

But measuring what effect, if any, cloud seeding had on measurable rain or snow proved very difficult. Researchers compared the amount of precipitation from randomly seeded clouds with similar clouds that were not seeded, but such statistical analysis produced mixed results, partly because natural precipitation is so variable that it is difficult to pick out the signal from the noise. Other work has indicated that cloud seeding can boost precipitation at specific locations, but left open the question of whether the increase in precipitation extended across significant areas.

To tackle the question, NSF and the Idaho Power Company launched a major field project in the winter of 2017 called SNOWIE (Seeded and Natural Orographic Wintertime clouds — the Idaho Experiment). Researchers used airborne and ground-based radars, high-resolution snow gauges, and computer modeling to quantify the impact of injecting silver iodide into clouds over the Payette Basin region north of Boise. The seeding aircraft released silver iodide along a flight path that resulted in a zigzag pattern of seeding effects in the clouds.

Scientists used the Doppler on Wheels radar to measure snowfall in the Idaho mountains that was generated by cloud seeding during the SNOWIE field project. Photo by Joshua Aikins via NCAR

This approach enabled the research team to observe the entire process and compare the side-by-side seeded and unseeded areas.

“We tracked the seeding plume from the time we put it into the cloud until it generated snow that actually fell onto the ground,” said Katja Friedrich, a professor at the University of Colorado Boulder and lead author of the new study.

The results show that, on at least three occasions, the seeding measurably boosted the snowfall across the targeted watershed. A cloud seeding flight on January 19, 2017, for example, generated snow for about 67 minutes, dusting roughly 900 square miles of land with about a tenth of a millimeter of snow above the minimal amount that was falling naturally.

The three cases highlighted in the study produced a combined total of 571 acre feet of water, or the equivalent content of about 285 Olympic-sized swimming pools.

Other cloud seeding attempts, however, were not so easily detected and may not have been successful. Tessendorf said the research team is continuing to analyze 18 additional attempts during SNOWIE in order to learn under what conditions the seeding effect can be detected and result in an increase in precipitation.

he results from SNOWIE can be used to improve computer models of cloud seeding processes and better inform officials as they make decisions about their particular priorities, Tessendorf said. Ski resorts might want to increase snow on selected days, whereas water managers would want to build up snowpack over the course of the winter in order to generate additional spring runoff.

“We’re going to need to dig deeper into the data and further quantify the seeding impact,” Tessendorf said. “It’s important to find out whether this enhances snowpack in a way that meets specific needs. ”

About the article

Title: Quantifying snowfall from orographic cloud seeding
Authors: Katja Friedrich, Kyoko Ikeda, Sarah A. Tessendorf, Jeffrey R. French, Robert M. Rauber, Bart Geerts, Lulin Xue, Roy M. Rasmussen, Derek R. Blestrud, Melvin L. Kunkel, Nicholas Dawson, and Shaun Parkinson.
Publication: Proceedings of the National Academy of Sciences

Thunderclouds building over the Rocky Mountains, shot as a short pano with an iPhone.

From Colorado Public Radio (Grace Hood):

The end result was a critical research finding: On three occasions, injecting clouds with silver iodide generated significant precipitation, more than doubling the rate of snowfall that had been falling naturally…

Cloud seeding is the deliberate injection of substances like silver iodide by airplane to create precipitation. The practice dates back to the 1940s when American chemist Vincent Schaefer used airplanes — and even cannons — to inject clouds with silver iodide or dry ice. While the industry around cloud seeding has existed for decades in the United States, the ability of science to verify results has been more ambiguous.

Scientists flew an airplane that had high-resolution cloud radar that could see features in clouds that are undetectable to the naked eye. Scientists also positioned mobile Doppler radars on wheels that storm chasers use high in the mountains above basins to observe changes in weather.

“Having these mobile radars positioned up on top of mountain ridges to be able to see over the basins where we were targeting cloud seeding, we were able to get measurements that we wouldn’t have seen otherwise,” [Sarah] Tessendorf said.

Eric Hjermstad, field operations director, Western Weather Consultants, lights a cloud seeding generator north of Silverthorne, Colorado. Photo credit: Denver Water

From KUNC (Luke Runyon):

A lot of the current water scarcity problems in the Southwest could be eased if it just snowed more and with a regular frequency in the high country of Colorado, Utah and Wyoming. More snow means more time to deal with the Colorado River’s fundamental supply and demand imbalance.

The onus to correcting that imbalance often falls more on the demand side of the equation, with myriad policy pushes that either incentivize or force people to use less water. On the supply side, options are limited.

There’s one tempting proposition for western water managers currently feeling the pressure to dole out cutbacks to users due to the region’s ongoing aridification — inducing clouds to drop more snow.

For decades, states have invested in weather modification programs, also known as cloud seeding, in the hopes of boosting precious snowpack. The practice showed up in a recent agreement among Colorado River Basin states, and investment is expanding, with water agencies in Wyoming and Colorado for the first time putting funds toward aerial cloud seeding, rather than solely relying on ground-based generators.

“I can say that we’re up significantly in the last 24 months on the number of smaller large-scale programs that we’re modeling and completing feasibility studies for,” says Neil Brackin, CEO of Weather Modification, Inc., a North Dakota-based cloud seeding company that operates across the Western U.S.

Brackin’s company is in charge of the Colorado and Wyoming aerial programs, flying cloud seeding operations when moisture-laden snow storms arrive in northern Colorado’s Never Summer range or southern Wyoming’s Medicine Bow and Sierra Madre ranges…

It’s not snowing when we visit the generator, but Hjermstad agrees to fire it up to demonstrate how it works. First, he gets propane flowing and then turns on a valve to the silver solution. With a fire starter, he lights the chimney on top. A bright orange flame flares from the generator, sending microscopic bits of silver iodide into the air.

If there was a storm right now and the wind was blowing the right direction, Hjermstad says, this generator could be influencing how much snow it eventually drops…

There is a certain class of clouds that are ripe for seeding, he says. Some clouds arrive in Colorado full of supercooled liquid water, but they’re not dropping that moisture. By injecting small particles into the cloud, a snowflake is able to form. The silver iodide acts as the “seed,” which enables the growth of a new ice crystal. That new snowflake can ricochet through the cloud, amplifying its impact…

From late November to April, Hjermstad keeps an eye on each weather system forecast to drop snow or pass over his generators. If it looks promising, he’ll contact the landowners where the generator sits, tell them when to turn it on and turn it off, and watch its track on radar with ground truthing courtesy of Colorado’s highway webcams.

For decades, the practice has had a problem with its reputation. Anecdotal accounts from farmers and ski resort owners confirmed cloud seeding effectiveness. Recent scientific studies have given it more credence, but top experts in the field argue there’s still a lot we don’t know about how well cloud seeding works…

Parked in a hangar outside Laramie, Wyo., we’re sitting inside the small research plane French uses to study clouds. To get to know a cloud, he says, you can’t just look at it from the outside, you need to get inside it. An expensive suite of on board instruments lets him look at how snow forms in real time.

“Ice crystals come in many many different shapes,” French says. “They can look like six-sided plates. They can look like long needles or columns. They can look like dendrites, which is kind of the typical snowflake shape.”

For years, French has devoted much of his research to understanding the science behind cloud seeding. In 2017 he partnered with the Idaho Power Company and other researchers to fly the research plane behind another plane that was seeding clouds. The result was a series of scientific articles. A 2018 report French co-authored showed for the first time how aerial cloud seeding worked…

The study, called “Seeded and Natural Orographic Wintertime Clouds: The Idaho Experiment” (SNOWIE) and conducted in the Payette River basin near Boise, Idaho, was a big deal. Before then, no one had solid evidence that showed the physics of cloud seeding working in the real world.

With new data in hand, French was able to say, “Yes, the amount of snow that was falling at this location increased.”

That might sound like a definitive endorsement of cloud seeding effectiveness. But the scientists producing the research are circumspect about their findings, and ready to caution people from taking away too much from SNOWIE’s early results…

Sarah Tessendorf is a researcher at the National Center for Atmospheric Research in Boulder, Colo. and worked with French on SNOWIE. People ask her frequently if cloud seeding works. And she says it depends on how you define “work.” If the question is whether or not cloud seeding is capable of producing more ice inside a cloud, then the answer is yes. But more often than not, the question is more complicated and people are hoping for more than that.

“So, sometimes the question … is, ‘Does it produce additional snowpack on the ground?’ And we’re still working to try to answer that question,” Tessendorf says.

Tessendorf is cautious about what she’s currently able to prove when it comes to cloud seeding. In the past, studies have shown the practice could boost snowpack by up to 15 percent. Tessendorf says the increase in snowpack cited in those studies has been a moving target over the years, with varying levels of rigorous data gathering. When she and other researchers want solid proof, they’re looking for a 95 percent level of confidence that cloud seeding caused the increase, and it wasn’t just a serendipitous series of storms…

In a gilded Las Vegas conference room in December 2017, water managers detailed their solutions to the Colorado River basin’s chronic water scarcity, and how to wean the Southwest from total reliance on the overtaxed river.

A representative from the Upper Colorado River Commission laid out what Colorado, Wyoming, New Mexico and Utah would bring to the table. A three-pronged Drought Contingency Plan included a focus on demand management, which would create a dedicated pool of saved water within Lake Powell. Another prong dealt with reservoir operations to streamline decision making between state and federal agencies. The third was a re-commitment to weather modification programs which had been in place in some form since 2007.

In mid-2018, before wrangling over Colorado River Drought Contingency Plans reached a fever pitch in the river’s Lower Basin, water agencies in California, Arizona and Nevada agreed to spend upwards of $1.5 million each year on cloud seeding programs in the watershed’s upper reaches.

“The reason that cloud seeding is being implemented on a relatively large scale in the Colorado River basin is it’s a very low-risk, high-reward scenario,” says Dave Kanzer, an engineer with the Colorado River District and manager of the Central Colorado Mountain River Basin Weather Modification Program, which receives funds from Lower Basin water agencies.

If you’re a water manager in the Southwest, it’s easy to think of cloud seeding like an extra battery for a smartphone. The guy selling the battery tells you it will probably only charge your phone another four or five percent, maybe more if you plug it in at exactly the right time. So it’s not reliable, but it’s the cheapest on the market. Every other battery is expensive and takes years to make. And if a lot of people are counting on you to make a call, you might just be willing to buy the battery, even if it ends up doing nothing in the end.

Kanzer says investors understand the risks involved with cloud seeding. They’re not under a delusion that it will be the basin’s saving grace…

Colby Pellegrino is with the Southern Nevada Water Authority, the water utility for Las Vegas, and says her agency’s investment in Upper Basin cloud seeding is worthwhile.

The University of Wyoming King Air (UWKA) research aircraft supports a large variety of instrumentation, and is configurable for measurements of cloud properties, air motion, turbulence and fluxes, atmospheric chemistry and aerosols. A research crew of three to four can typically be accomodated with an approximate four hour flight endurance and a maximum flight level of 28,000 ft. The UWKA has a payload capacity of up to 1,650 lbs, supporting the suite of instrumentation maintained by the UW Research Flight Center as well as user-supplied equipment. The UWKA is commonly configured to accomodate the University of Wyoming Cloud Radar (WCR) and University of Wyoming Lidar (WCL) systems.

Here’s a release from the University of Wyoming:

Two University of Wyoming researchers contributed to a paper that demonstrated, for the first time, direct observation of cloud seeding using radar and gauges to quantify the snowfall. Traditionally, cloud seeding — used to increase winter snowpack — has been evaluated using precipitation gauges and target/control statistics that led mostly to inconclusive results.

The research, dubbed SNOWIE (Seeded and Natural Orographic Wintertime Clouds — the Idaho Experiment), took place Jan. 7-March 17, 2017, within and near the Payette Basin, located approximately 50 miles north of Boise, Idaho. The research was in concert with Boise-based Idaho Power Co., which provides a good share of its electrical power through hydroelectric dams.

“This looks at how much snow falls out of seeded clouds at certain locations. That’s what’s in this paper,” says Jeff French, an assistant professor in UW’s Department of Atmospheric Science and fourth author of the paper. “We want to see if we can apply what we learned over a number of cases over an entire winter.”

The paper, titled “Quantifying Snowfall from Orographic Cloud Seeding,” appears in the Feb. 24 (today’s) issue of the Proceedings of the National Academy of Sciences (PNAS), one of the world’s most prestigious multidisciplinary scientific journals, with coverage spanning the biological, physical and social sciences.

The paper is a follow-up to a previous PNAS paper, by the same research team, titled “Precipitation Formation from Orographic Cloud Seeding,” which was published in January 2018. That paper focused on what happens in the clouds when silver iodide is released into the clouds. In the case of the SNOWIE Project, the silver iodide was released by a second aircraft funded through Idaho Power Co., while the UW King Air took measurements to understand the impact of the silver iodide, French says.

Katja Friedrich, an associate professor and associate chair of atmospheric and oceanic sciences at the University of Colorado-Boulder, was the newest paper’s lead author. Bart Geerts, a UW professor and department head of atmospheric science, was sixth author on the paper. Other contributors were from the University of Illinois at Urbana-Champaign, the National Center for Atmospheric Research (NCAR) and Idaho Power Co.

Throughout the western U.S. and other semiarid mountainous regions across the globe, water supplies are fed primarily through snowpack melt. Growing populations place higher demand on water, while warmer winters and earlier spring reduce water supplies. Water managers see cloud seeding as a potential way to increase winter snowfall.

“We tracked the seeding plumes from the time we put the silver iodide into the cloud until it generated snow that actually fell onto the ground,” Friedrich says.

French credits modern technology, citing the use of ground-based radar, radar on UW’s King Air research aircraft and multiple passes over a target mountain range near Boise, with making the detailed cloud-seeding observations happen. Despite numerous experiments spanning several decades, no direct, unambiguous observation of this process existed prior to SNOWIE, he says.

Over the years, research of cloud seeding “has been clouded,” so to speak, Geerts adds. He says it was difficult to separate natural snowfall and what amount was actually produced through cloud seeding. However, this study was able to provide quantifiable snowfall.

“Natural snowfall was negligible. That really allowed us to isolate snow added through cloud seeding,” Geerts says. “However, we are still in the dark where there is lots of natural snowfall.”

Following a brief airborne seeding period Jan. 19, 2017, snow fell from the seeded clouds for about 67 minutes, dusting roughly 900 square miles of land in about one-tenth of a millimeter of snow, based on the team’s calculations. In all, that cloud-seeding event and two more later that month produced a total of about 235 Olympic-sized swimming pools’ worth of water.

Other observations where snow from cloud seeding was measured took place Jan. 20 and Jan. 31 of that year.

In all, the UW King Air made 24 research flights or intense observation periods (IOPs) lasting 4-6 hours each during SNOWIE. Of those IOPs, cloud seeding occurred during 21 of the flights. During the last three flights, Idaho Power had to suspend cloud seeding because there was so much snow in the mountains already.

While a good deal of research took place aboard the King Air, much of it also occurred on the ground. Numerical modeling of precipitation measurements was conducted using the supercomputer, nicknamed Cheyenne, at the NCAR-Wyoming Supercomputing Center. The numerical models simulated clouds and snow precipitation — created in natural storms and with cloud seeding — over the Payette Basin near Boise. The numerical models also allow researchers to study future storm events where measurements have not been obtained in the field.

While the 24 cloud-seeding flights by King Air was a good start, Geerts says, in an ideal world, even more flights are necessary to learn more about cloud seeding in other regions of the country.

Friedrich adds that the research is an important first step toward better understanding just how efficient cloud seeding can be at creating those winter wonderlands.

“Everyone you talk to will say, even if you can generate a little bit more snow, that helps us in the long run,” she says.

French says the team has applied for a new National Science Foundation grant to continue analyzing cloud-seeding data collected from the remaining research flights during 2017.

“We will look at areas where natural snowfall occurs,” French says. “We’ll take what we learned and see if we can quantify how much snow was produced through silver iodide in areas already receiving snow.

“When we get done with the next three years, we’d like to go out and make similar-type measurements in Wyoming, Colorado or Utah, where clouds may have different characteristics,” French adds. “We can broaden the types of clouds we can sample.”

This video shows Drone footage from the top of Granite Peak in Idaho as we were digging out the Doppler On Wheels (DOW) mobile radar, RV trailer, and porta potties that were deployed for the Seeded and Natural Orographic Wintertime Clouds: The Idaho Experiment (SNOWIE) scientific field campaign. This site was called the “Snowbank” site during the project due to the roadway that leads to Snowbank Mountain just to the north of Granite Peak. I was the CU Boulder graduate student lead working with the Center for Severe Weather Research (CSWR) to operate the DOWs during SNOWIE.

To learn more about the SNOWIE project, check out the links below:
https://www.eol.ucar.edu/field_projec…
http://www.cswr.org/projects/snowie/

The January 2020 newsletter is hot off the presses from the Water Information Program

Click here to read the newsletter. Here’s an excerpt:

Demand Management – a Hot Topic!!
There was an in-depth conversation around the Demand Management topic!

Celene Hawkins stated that the Demand Management workgroups are just at the beginning stages of work and there are still many questions. There is a greater need for coordination and keeping a steady pace of the work, while not moving too quickly so as to not miss things, as these are very complicated issues and need to take that time that is needed to do the work. There will be a joint IBCC and Demand Management work-group meetings that will take place March 4-5 where discussion could take place about that better coordination and how the CWCB can support the work-groups moving forward.

Russell George stated that the IBCC is not a work-group in Demand Management, they intentionally stand aside because they wanted to be ready as the IBCC to pick any particularly thorny question with the statewide implication that needed their help. The IBCC believes that at this point in time, and because of what’s going on with the river as a whole and the water levels of the big reservoirs, Demand Management becomes probably one of the most important issues for discussion on Colorado water issues that there is today. George explained that we owe it to the other Upper Basin states who are going through this drill, to work together to find an approach that works in all four states or to learn together that Demand Management can’t be done. Whatever conclusion is reached, it needs to be based on open and careful consideration of Demand Management as a tool that is being evaluated, as called for in the Drought Contingency Plans and Legislation.

Southwestern Water Conservation District Area Map. Credit: SWCD

As the Southwest dries out, water managers increasingly look to cloud seeding — The Durango Herald

Cloud seeding ground station. Photo credit H2O Radio via the Colorado Independent.

From The Durango Herald (Jonathan Romeo):

For decades, Western states have tried to offset long-term drying trends and dwindling water supplies of the region by sending up a specialized concoction into the atmosphere as winter storms approach, which proponents say boosts snowfall.

Across a sliver of Colorado from Telluride to Pagosa Springs, a total of 36 cloud-seeding generators are strategically placed, typically 5 miles apart, to cover a wide range of the high country of the San Juan Mountains for this purpose.

In 2020, the Southwestern Water Conservation District has set aside $27,000 for a new remote generator. While the station’s location is being decided, the aim is to place it at a higher elevation site where there is a gap in the network of generators.

“The majority of our water supply comes from snowpack, so if we can provide any additional amount, it has a huge benefit to our basin,” said Frank Kugel, executive director of SWCD, which represents nine counties in Southwest Colorado.

Waters managers who rely on the Colorado River are dealing with an array of issues as more people move into the region and demands increase on a waterway that is seeing less water every year because of issues directly related to climate change.

In adapting to this new reality, cloud seeding, they say, is just one part of the attempted solution…

Does it work?

How much additional snow falls as a result of cloud seeding has been a hot topic among water managers for years, and most agree, more detailed research needs to happen to pin down just how much additional snow is extracted from the practice.

Yet, most accept an estimated range between 2% to 15% more snow per storm.

Statewide, about $1.2 million is spent annually toward cloud seeding, with money coming from local and state water districts, as well as lower basin states that rely on the Colorado River, said Andrew Rickert, program manager for the Colorado Water Conservation Board.

Supporters of the project have said that for every $1 in cost, about $3 worth of water is produced…

The future

Better technology, more generators in high-elevation spots and more stations in general are the top priority with cloud seeding going further.

Experiments have been conducted in recent years that show releasing silver iodide by plane gets more out of storms, but the practice is expensive, and cost-prohibitive, Kugel said.

Southwestern Water Conservation District, along with its partners, will take the coming weeks to find the best spot for the new remote generator in the region. The district spends about $117,000 on the entire cloud-seeding effort in the region.

Cloud-seeding graphic via Science Matters

The latest “The Current” newsletter is hot off the presses from the #EagleRiver Watershed Council

Photo credit: Eagle River Watershed Council

Click here to read the newsletter. Here’s an excerpt:

Cloud Seeding Discussion with Colorado River District

A big thank you to our presenters, Dave Kanzer with the Colorado River District and Eric Hjermstad with Western Weather Consultants for a great community discussion. We had about 50 folks join us at Loaded Joe’s to learn about the weather modification tool being implemented locally.

Missed it? You can watch a recorded version here thanks to High Five Access Media and the underwriting of Eagle River Water & Sanitation District!

Cloud-seeding graphic via Science Matters

The San Juan Water Conservancy District ponies up $1,000 for cloud-seeding research

State cloud seeding programs. Graphic credit: The Huffington Post

From The Pagosa Sun (Chris Mannara):

Following a presentation earlier in the day, the San Juan Water Conservancy District (SJWCD) Board of Directors opted to see if ef- forts from cloud seeding could produce any re- sults that could be seen locally before providing funding to cloud seeding efforts.

The cloud seeding presentation was given to the board during a work session on Tuesday by Eric and Mike Hjermstad from Western Weather Consultants LLC, and following the work ses- sion, the board had a possible action item on whether or not to fund cloud seeding efforts for the southwest basin.
In the draft budget, the SJWCD has $1,000 set aside for potential cloud seeding funding…

The effectiveness and amount of extra moisture that is produced by cloud seeding ef- forts has been debated for years, SJWCD board member Al Pfister noted…

[Bill] Hudson later made a motion that suggested the SJWCD look into whether or not it could help finance the research of cloud seeding operations in the district’s watershed and would task SJWCD consultant Renee Lewis to conduct this project. The motion passed unanimously.

Upper #ColoradoRiver Basin #drought contingency plan depends on rights holders bypassing water #COriver #aridification

The looming possibility of mandatory curtailment of water use has raised concerns among Western Slope water managers, who feel that such cuts could harm Western Slope agricultural, such as this hay filed in the Yampa River basin. However, as water levels continue to drop to record lows in Lake Powell, mandatory curltailments are being discussed as a real possibility, especially by Front Range water managers. Photo credit: Brent Gardner-Smith/Aspen Journalism

From The Steamboat Pilot & Today (Eleanor C. Hassenbeck):

The collective group of [recently signed] agreements is called the Colorado River Drought Contingency Plan.

It aims to raise the unprecedented low water levels in the largest reservoirs on the Colorado River system, Lake Powell and Lake Mead, to enable them to continue to deliver water and produce hydropower.

In Colorado, it calls for three possible actions:

  • Creating a bank of stored water in federally owned reservoirs upstream of Lake Powell. This water would be released into Lake Powell in order to make sure Colorado continues to meet obligations to deliver a certain amount of water to downstream states under the Colorado River Compact.
  • Increasing cloud seeding and removing deep-rooted, invasive plants that take up a lot of water, such as tamarisk.
  • Creating a voluntary program that would temporarily pay agricultural water users to fallow their land and send water they have a right to downstream. This is called demand management.
  • Of the options on the table, demand management — the option that would pay farmers not to use their water — is the one most likely to impact Routt County…

    Demand management is still only a hypothetical, so the Yampa River Basin could opt out of a program if it doesn’t work for the area.

    The Colorado Water Conservation Board has assembled workgroups on topics related to demand management. These groups are now meeting behind closed doors to develop preliminary reports outlining how the program might work.

    Brown said once these reports are completed and released to the public, there will be opportunities for community members to provide input on the idea. She said there will be the “opportunity for a real, thoughtful conversation, especially in the Yampa and White (river) basins.”

    Cloud seeding part of efforts to put the brakes on #snowpack decline #aridification

    Cloud-seeding graphic via Science Matters

    From KUNC (Luke Runyon):

    A lot of the current water scarcity problems in the Southwest could be eased if it just snowed more and with a regular frequency in the high country of Colorado, Utah and Wyoming. More snow means more time to deal with the Colorado River’s fundamental supply and demand imbalance.

    The onus to correcting that imbalance often falls more on the demand side of the equation, with myriad policy pushes that either incentivize or force people to use less water. On the supply side, options are limited.

    There’s one tempting proposition for western water managers currently feeling the pressure to dole out cutbacks to users due to the region’s ongoing aridification — inducing clouds to drop more snow.

    For decades, states have invested in weather modification programs, also known as cloud seeding, in the hopes of boosting precious snowpack. The practice showed up in a recent agreement among Colorado River Basin states, and investment is expanding, with water agencies in Wyoming and Colorado for the first time putting funds toward aerial cloud seeding, rather than solely relying on ground-based generators.

    State cloud seeding programs. Graphic credit: The Huffington Post

    Cloud seeding starts up in #Wyoming

    Cloud-seeding graphic via Science Matters

    From KUNC (Luke Runyon):

    On Nov. 15 Wyoming started using small airplanes to flare silver iodide into snowstorms that roll into the Sierra Madre and Medicine Bow mountains, north of the Colorado-Wyoming border. North Dakota-based Weather Modification Inc. operates the planes. Since starting this fall, WMI has seeded clouds over southern Wyoming four times.

    Now, the Jackson County Water Conservancy District wants to expand the practice near the headwaters of the North Platte River in northern Colorado. The district is seeking a permit from the state’s Water Conservation Board to begin aerial seeding during winter storms.

    Recent studies have shown cloud seeding can marginally increase snowpack in theory. But a 2018 study from researchers at the University of Wyoming and the University of Colorado said big questions still remain regarding the practice’s effectiveness.

    If the state approves the permit, this would be Colorado’s first aerial cloud seeding program.

    Wyoming’s program costs the state roughly $425,000, with Cheyenne’s water utility contributing $45,000. The state also oversees cloud seeding towers in the Wind River mountain range, which are partially paid for by water agencies in Arizona, California and Nevada.

    Some of Colorado’s cloud seeding operations receive funding from the same states, all in the Colorado River’s lower basin. Earlier this year, water managers in the seven basin states signed a new agreement to continue cloud seeding operations in the southern Rockies, allocating up to $2 million annually. The practice was included as a way to increase water supplies in Drought Contingency Plans being negotiated now, and recently approved by Colorado’s top water authority, the Colorado Water Conservation Board.

    Aerial seeding in northern Colorado could begin later this month.

    #ColoradoRiver: “We’re really talking about augmenting or increasing the water supply [via cloud seeding] for 40 million people that rely on the Colorado River Basin” — Dave Kanzer #COriver #aridification @ColoradoWater

    From Aspen Public Radio (Elizabeth Stewart-Severy):

    The Colorado River District says adding to the snowpack is one way to address dwindling water supplies; a study in Wyoming showed that, when the conditions are right, cloud seeding can increase snowfall by 5 to 15 percent per storm. That translates to a slight increase in water supplies — a 1 to 5 percent increase in snowpack-derived water.

    Dave Kanzer, an engineer with the River District, said more efficient storms with more snowfall can mean more water across the West.

    “We’re not just talking about one county and one city,” Kanzer said. “We’re really talking about augmenting or increasing the water supply for 40 million people that rely on the Colorado River Basin.”

    The River District has ongoing cloud seeding operations across Colorado, all along the Continental Divide, but not in Aspen and Pitkin County.

    “We are proposing to fill in those areas upstream toward Independence Pass, to include all of the Ski Co properties, and all of the upper Roaring Fork Watershed,” Kanzer said.

    He will present a proposal for a three-year cloud-seeding program to Pitkin County’s Healthy Rivers Board at its meeting this Thursday. The River District has also been in talks with the City of Aspen and Aspen Skiing Company.

    From Aspen Public Radio (Elizabeth Stewart-Severy):

    Kanzer says the science is clear, but the process is not precise. A study conducted in Wyoming shows the conditions are only right in about 30 percent of storms, but when they are, cloud seeding can increase snowfall. That snowpack contributes to the water supply not just in the Roaring Fork Valley, but across the west.

    “Even if we only increase the water supply by a small fraction, it can have wide ranging benefits,” Kanzer said, including more water in local rivers and more snow on the mountain.

    The River District wants to see more cloud seeding activities in the Aspen area. On Thursday, the Pitkin County Healthy Rivers Board will hear a proposal from Kanzer about expanding cloud seeding activities. He also has met with City of Aspen water officials and Aspen Skiing Company.

    Rich Burkley, vice president of mountain operations for SkiCo, said the company is interested in supporting the River District, but not as a business investment. The small increase in snowfall doesn’t translate to extra powder days for skiers and riders.

    “A 10-inch storm going to a 10.5-inch storm, doesn’t really do too much,” Burkley said.

    While cloud seeding might not be a boon for powder skiers, Burkley said SkiCo is supportive of any measures that might help the water supply. The company has offered to participate as a site for the generators and to help with manpower to operate them.

    The River District is looking for funding from Pitkin County’s Healthy Rivers Board and the City of Aspen; the proposal would then need a permit from the State of Colorado.

    UW Researcher Leads Study of First Quantifiable Observation of Cloud Seeding

    Cloud-seeding graphic via Science Matters

    From the University of Wyoming:

    A University of Wyoming researcher contributed to a paper that demonstrated, for the first time, direct observation of cloud seeding — from the growth of the ice crystals through the processes that occur in the clouds to the eventual fallout of the ice crystals that become snow — and how the impacts could be quantified.

    The research, dubbed SNOWIE (Seeded and Natural Orographic Wintertime Clouds — the Idaho Experiment), took place Jan. 7-March 17, 2017, within and near the Payette Basin, located approximately 50 miles north of Boise, Idaho. The research was in concert with Boise-based Idaho Power Co., which provides a good share of its electrical power through hydroelectric dams.

    “No one has ever had a full comprehensive set of observations of what really happens after you seed the cloud,” says Jeff French, an assistant professor in UW’s Department of Atmospheric Science. “There have only been hypotheses. There has never been a set of observations from one campaign that shows all the steps that occur in cloud seeding.”

    French credits modern technology, citing the use of ground-based radar, radar on UW’s King Air research aircraft and multiple passes of the mountain range near Boise with making the detailed cloud-seeding observations happen. Despite numerous experiments spanning several decades, no direct observation of this process existed before SNOWIE, he says.

    French is the lead author of a paper, titled “Precipitation Formation from Orographic Cloud Seeding,” which appears in the Jan. 22 (today’s) issue of the Proceedings of the National Academy of Sciences (PNAS), one of the world’s most prestigious multidisciplinary scientific journals, with coverage spanning the biological, physical and social sciences.

    Other contributors to the paper were from the University of Colorado-Boulder, University of Illinois at Urbana-Champaign, the National Center for Atmospheric Research (NCAR) and Idaho Power Co.

    “SNOWIE was a great collaborative effort, and it shows the value of private, public and academic partnerships,” says NCAR scientist Sarah Tessendorf, a co-author of the paper.

    Tessendorf notes that SNOWIE grew out of research that Idaho Power Co. had conducted with NCAR to improve its cloud-seeding program. This included the development of high-resolution computer modeling approaches to simulate cloud seeding, enabling researchers to better evaluate its impacts.

    “This research shows that modern tools can be applied to long-standing scientific problems,” says Nick Anderson, program director in the National Science Foundation (NSF)’s Division of Atmospheric and Geospace Sciences, which funded the study. “We now have direct observations that seeding of certain clouds follows the pathway first theorized in the mid-20th century.”

    Cloud seeding is a process by which silver iodide is released into the clouds, either from the air or via ground-based generators. In the case of the SNOWIE Project, the silver iodide was released by a second aircraft funded through Idaho Power Co., while the UW King Air took measurements to understand the impact of the silver iodide, French says.

    In all, the UW King Air made 24 research flights or intense observation periods (IOPs) lasting 4-6 hours each during SNOWIE. Of those IOPs, cloud seeding occurred during 21 of the flights. During the last three flights, Idaho Power had to suspend cloud seeding because there was so much snow in the mountains already, French says.

    While a good deal of research took place aboard the King Air, much of it also occurred on the ground. Numerical modeling of precipitation measurements was conducted using the supercomputer, nicknamed Cheyenne, at the NCAR-Wyoming Supercomputing Center. The numerical models simulated clouds and snow precipitation — created in natural storms and with cloud seeding — over the Payette Basin in Boise. The numerical models also allow researchers to study future storm events where measurements have not been obtained in the field.

    “Midterm, it will help with those simulations we are running on Cheyenne,” French says. “Long term, we can answer questions with this data and simulations on how effective cloud seeding is in orographic clouds, and what conditions one can expect cloud seeding to be effective.”

    Throughout the western U.S. and other semiarid mountainous regions across the globe, water supplies are fed primarily through snowpack melt. Growing populations place higher demand on water, while warmer winters and earlier spring reduce water supplies. Water managers see cloud seeding as a potential way to increase winter snowfall.

    “Ultimately, water managers and state and federal agencies can make the decision whether cloud seeding is a viable option for them in terms of adding additional water to their supplies in addition to snowpack in the mountains,” French says.

    From Science Magazine (Angus Chen):

    …despite decades of cloud seeding operations, proof that the technique works outside miniaturized clouds created in the lab has been elusive. One reason: Instruments of decades past couldn’t measure water droplet size in clouds in real time. Without knowing how a cloud evolves after seeding, scientists were unsure whether the silver iodide was doing anything at all. Another: The chaotic nature of weather makes controlled, natural experiments almost impossible. “Once you seed, you’re contaminating the cloud. You can’t repeat the experiment because you’ll never have the same atmospheric conditions again,” says Katja Friedrich, an atmospheric scientist at the University of Colorado in Boulder.

    But newer instruments convinced Friedrich and her colleagues that the time was ripe for another approach—and the National Science Foundation and Idaho Power provided the funding. The team took its experiment to the mountains of southwestern Idaho, where it waited until supercooled clouds appeared in the sky. At temperatures of 0°C to –15°C, they are cold enough to freeze, but are at low odds of doing so.

    When the right clouds came along, the team sprang into action. It launched one aircraft that made laps between two ground-based radars, dropping canisters that spread silver iodide into the clouds. The same plane also flew through the cloud while streaming silver iodide from its wings. Another plane loaded with cloud measuring equipment paced a perpendicular path to take readings.

    At first, there was nothing. “The radar can only see [water] particles that are big enough, and these clouds had tiny droplets not detectable by radar,” Friedrich says. “Suddenly, we saw lines appear. It was really astonishing.” The zig-zagged lines matched the flight path of the first plane. Within these lines, the cloud’s water particles were getting bigger as they hit the silver iodide and froze. After a couple of hours, the snowflakes had grown from a few microns in diameter to 8 millimeters in diameter—heavy enough to fall to the ground, Friedrich and her colleagues report today in the Proceedings of the National Academy of Sciences. “We were super, super excited. Nobody had seen that before,” she says.

    The experiments have also been met with enthusiasm from cloud seeding companies. “Those of us working on cloud physics for a long time have felt that [cloud seeding] was working,” says Bruce Boe, a meteorologist at cloud-seeding company Weather Modification in Fargo, North Dakota. “This verification and incontrovertible evidence this is occurring is really, really nice for us.”

    Still up for study is whether the approach is economical. “Does it make enough snow to make an impact on a water budget?” Friedrich wonders. “We still have to answer those fundamental questions.”

    Clouds with a Silver Lining: Seeding Storms to Boost the #ColoradoRiver — @COindependent #COriver

    A cloud seeding generator near the Winter Park ski area in Colorado. (Desert Research Institute (DRI))

    From The Colorado Independent (H20 Radio):

    Clouds with a Silver Lining: Seeding Storms to Boost the Colorado River

    In much of the West, demand for water is projected to outpace supply, especially in the Colorado River basin, which provides drinking water to over 40 million people. There are various strategies to close the gap–some controversial like building new reservoirs and others more widely accepted like conservation.

    But what if you could just wave a magic wand and make it rain or snow? It’s not impossible and in fact, it’s been going on in the West for years.

    It’s called weather modification, better known as “cloud seeding.” With a changing climate and drier future, many are looking to the technique to boost snowpack in the mountains to meet growing water needs. More snow, even a small percentage can mean more runoff—and more water to cities and farms.

    Back in the fall we drove with Joe Busto from the Colorado Water Conservation Board out of Fraser, Colorado, in the Rocky Mountains to see a cloud seeding operation firsthand—and meet some of the people involved. Busto says they’re trying to “put extra snow in the bank where you need it for water supplies” and that cloud seeding has been shown to add anywhere from 5 to 15 percent to the snowpack.

    Snow pit at Winter Park — sampling for silver iodide. Photo via the Desert Research institute.

    There are about 40 total sponsors of cloud seeding in Colorado, including regional water districts, the state of Colorado, local water districts, cities, towns, counties, and nine of the state’s 28 ski areas.

    With us in the car is Maria Pastore, who represents some of those entities that range from Denver Water and Colorado Springs Utilities to ski areas like Winter Park, which we’re not too far from as we drive. For a state with much tension around moving water across the Continental Divide, Pastore says cloud seeding is being embraced by both sides. She says they have a large group of collaborative sponsors, and cloud seeding is probably one of the arguably least contentious programs for the West Slope and East Slope partners.

    Pastore’s group works with ski areas for cloud seeding because you get more bang for the buck. They’re already located in places that typically get a lot of snow—and they provide a recreational benefit. After folks have schussed or snowboarded across it, the snow will melt and flow into the tributaries of the Colorado River to become drinking water and to turn turbines in hydroelectric dams.

    We arrive at a spot that could pass for a nice campsite. Parked on it is a small camouflage-painted trailer with a twenty-foot mast sticking up in the air—and a barrel on top. Waiting for us by the trailer is Jeff Dean of the Desert Research Institute, or DRI. Dean and his team are at this site to get the cloud seeding equipment, called the generator, ready for the season ahead. So how does cloud seeding work?

    Dean explains that cloud seeding is done by adding extra dust to the air. A typical cloud will only drop maybe five percent of its available moisture. They’re not very efficient. Inside every cloud droplet and every snowflake there is a piece of dust—nuclei that started the process. In cloud seeding, they’re just introducing a little bit more of that dust. They do that by burning silver iodide, which goes up in the air to start the growth of a crystal that eventually will turn into a snowflake.

    DRI has meteorologists watching several factors like wind speed, humidity, and temperature to identify the perfect moment to fire up the generator to hit their intended target, which in this case is the Winter Park ski area and Denver Water’s drainage.

    Dean is out here with us to demonstrate how they start up the equipment. With a tap on his laptop the generator begins to hum. Dean could have been in his office in Reno or on a beach in Maui to activate the system. We watch inside the barrel and after a few seconds a bright yellow, robust flame appears, which indicates that the silver iodide solution is starting to burn. Dean says that last year this generator produced 22 inches of snow for the ski area.

    So how do they know it wouldn’t have snowed anyway? They assess that by looking for traces of the silver iodide in the snow. DRI did an analysis at the Winter Park ski area where they went halfway up the lifts and did a full profile all the way to the ground by inserting test tubes every ten centimeters. They then weighed the samples and did a chemical analysis. They found trace amounts of the silver, which according to the state of Colorado, are at extremely low concentrations and not harmful.

    The cloud seeding program isn’t just being sponsored by providers in Colorado. Downstream users in other states who depend on a good Rocky Mountain snowpack are also on board. Joe Busto says that after the drought in early 2000s, it was bad in Colorado, but the state rebounded quickly because reservoirs are next to the mountains. But the lower basin states downstream on the Colorado River—Arizona, California, and Nevada—came knocking on the door and said, “Lake Powell and Lake Mead are drying out…”

    The result was a partnership among the Southern Nevada Water Authority that serves Las Vegas, the Central Arizona Project, and six agencies in California including the mega-one in L.A. All now help fund cloud seeding in Colorado.

    So while recent storms are thrilling skiers, a good base on the slopes this year may also contain a silver lining for water users hundreds of miles away.

    Detailed Colorado River Basin map via the U.S. Bureau of Reclamation.

    Cloud-seeding is gaining acceptance

    From the SummitDaily (Jack Queen) via The Aspen Times:

    [Larry] Hjermstad and his company, Western Weather Consultants, now run cloud seeding programs across the state, including in Summit County.

    For decades, local ski areas have paid him to send plumes of silver iodide up to their slopes when opportune storms approach, squeezing out a couple of extra inches of snow each time.

    In recent years, however, water managers on the Front Range and even states further down the Colorado River have started to pitch in some of the $250,000 to $300,000 it costs to run the program in the Summit County area, hoping the extra snow will flow into their water system when it melts.

    Here, in the Central Colorado Mountains River Basin, the company operates about 36 cloud seeding generators. They’re small, almost homebrew-looking devices that burn a solution of inert silver iodide and send it into the atmosphere.

    Some of the generators are on private land, and when Western Weather Consultants detects an optimal storm coming, it sends instructions to the landowners to fire them up. It varies, but Hjermstad says the process can boost snowfall by as much as 25 percent…

    SNAKE OIL OR SCIENCE?

    The concept of cloud seeding has been around since the 1940s, when Bernard Vonnegut (brother of author Kurt) discovered that silver iodide could produce ice crystals when introduced into cloud chambers.

    In those heady days, cloud seeding was heralded as a way to produce rain where there was none, boosting crop yields and filling reservoirs to the brim.

    That was a wild overstatement, and cloud seeding’s reputation suffered for it…

    Studies in Australia and Israel have debunked the idea that airplanes spewing silver iodide willy-nilly will do much of anything. But a targeted approach that hits the right clouds at the right time high in the mountains has gained scientific currency in recent years.

    Rio Grande Roundtable meeting recap

    Cloud-seeding graphic via Science Matters

    From The Alamosa News (Ruth Heide):

    Although there are currently no cloud seeding operations in the San Luis Valley, some folks believe this might be a good place for it.

    Joe Busto, who oversees weather modification permits for the Colorado Water Conservation Board, gave the Rio Grande Roundtable group a crash course on cloud seeding during its Tuesday meeting. The Valley-wide water group funds many water related projects in the Rio Grande Basin from ditch repair to reservoir rehab. The group was not asked for funding at this time.

    Busto said that another form of weather modification, hail cannons, previously operated in the San Luis Valley under a permit with Southern Colorado Farms, but the agricultural operation discontinued the practice.

    Cloud seeding occurs all around the region from Texas to North Dakota, Busto stated.

    Many of the cloud seeding operations in Colorado are associated with ski areas such as Vail, Crested Butte and Breckenridge, Busto explained. Others are connected to water districts. There are currently 110 machines in the state. He described the primary catalysts as either silver iodide, which is expensive but effective (and not harmful to the environment), or propane, which is cheaper.

    Before setting up a machine, plume dispersion tests are conducted to determine how the winds are blowing and from what direction so the cloud seeding operation can be set up to provide the most good.

    Operations are also the most effective when machines are set up at higher elevations, Busto explained.

    Roundtable member Travis Smith asked, “Is the Rio Grande ready to start participating in a winter time cloud seeding program?”

    Roundtable member Charlie Spielman said he saw this as a solution to the imbalance between water supply and demand.

    “Cloud seeding is the best opportunity within our reach of making a real dent in that supply/demand gap,” he said.

    He encouraged “getting a program going here … Let’s put something into this because I think this is our best chance.”

    Busto said he believed a lean cloud seeding operation could be put in place for about $60,000 a year. He said he believed there could be many benefits to this area as well as downstream.

    #ColoradoRiver: The @CWCB_DNR is installing a ceilometer in Winter Park #COriver

    Winter Park via MyColoradoLife.com.
    Winter Park via MyColoradoLife.com.

    From The Sky-Hi Daily News (Travis Poulin):

    At their October 4 meeting, the Winter Park Town Council passed a motion to allow a ceilometer to be installed on the roof of the Winter Park Town Hall. . A ceilometer is a device that uses a laser to determine the height of a cloud base.

    The town received a request from the Colorado Water Conservancy Board (CWCB), Denver Water and Winter Park Resort to place the device on the Town Hall building to aid them in their cloud seeding program. It will detect multiple layers of cloud height as well as measure the liquid water available in the clouds. The ceilometer will allow them to provide better forecasting for the cloud seeding program.

    In addition to the cloud seeding program, this device will be available to pilots flying into Grand County. The pilots can determine the base elevation of the clouds as they approach the runway at the Granby/ Grand County Airport. The ceilometer is approximately four feet tall and would be attached to an existing concrete pillar.

    The ceilometer will need electricity and Internet service. The electricity usage is approximately 5 amps per month (about 55 cents per month). The data usage is approximately a half a megabyte per month. The additional Internet service would not require upgrades as the current system has adequate space.

    The Winter Park Town Council, CWCB, Denver Water, and Winter Park resort are now in the process of drafting a Memorandum of Understanding (MOU) for the installation of the ceilometer. The council also determined they will need a lease agreement for the project.

    CLOUD SEEDING IN GRAND COUNTY

    There are currently two cloud seeding generators in Grand County—one to the north of the Younglife camp at Crooked Creek Ranch, and the other near Churches Park in Fraser. The generators are remotely operated and controlled from Reno, Nev. They have been in place since 2009.

    The Desert Research Institute (DRI) runs the cloud seeding program. According to their website, DRI currently has five cloud seeding operations: the San Juans (Mancos) Project, the San Miguel (Telluride) Project, Tahoe and Truckee basins, Walker Basin, and the Winter Park/ Denver Water Project. The purpose of the program is to augment snowfall in mountainous regions that supply water to northern and southern Nevada, and increase the snowpack and resultant runoff from the targeted basins.

    According to DRI website, ground-based generators are used to burn a solution of silver iodide, sodium iodide, salt and acetone to release microscopic silver iodide particles which can create additional ice crystals, then snow, in winter clouds. Weather conditions are selected to optimize fallout in targeted basins. Generators are remotely operated by telephone landline, by radio or by other types of wireless communication. A seeding aircraft is frequently used to augment ground seeding operations. The aircraft releases AgI from wing-mounted solution burners. Dry ice is also used occasionally to seed shallow cloud systems, including fog over airports.

    According to the website, benefits vary with the seasonal frequency of suitable weather opportunities. Research results have documented precipitation rate increases of a few hundredths to about two millimeters per hour due to ground-based seeding during the proper weather conditions. Based on the rate increases, estimates of augmented snow water from the DRI seeding program have varied from 20,000 to 80,000 acre-feet annually over the past 15 years of operation.

    Seasonal percentage increase estimates have varied from two percent to ten percent The cost of augmented water, based on the annual cost of the program, has ranged from $7 to about $18 per acre-foot, according to DRI.

    Cloud-seeding graphic via Science Matters
    Cloud-seeding graphic via Science Matters

    #ColoradoRiver: Remote-operated cloud seeder being installed above Dolores — KOAA.com #COriver

    instumentationcloudseedingresearchcolorado

    From the Associated Press via KOAA.com:

    A remote-operated cloud-seeding generator is being installed in the mountains above Dolores in an attempt to improve snowpack and runoff into McPhee Reservoir.

    Cloud seeders emit plumes of silver iodide into winter storm clouds to coax additional precipitation from clouds.

    There are about 30 cloud-seeding generators stretching in an arc from Telluride to Mancos to Pagosa Springs. Most of the units are 40-year-old designs and require an operator to turn them on and off when conditions warrant.

    The Cortez Journal reports that the Dolores Water Conservancy District has partnered with the Idaho Power Co. and Colorado Water Conservation Board on the project. Idaho Power has developed a more efficient remote-controlled generator that can be placed in locations higher in the mountains and closer to the clouds they seed.

    Cloud-seeding graphic via Science Matters
    Cloud-seeding graphic via Science Matters

    Cloud seeding: “It can’t replace dams or conservation” — Joe Busto

    Cloud-seeding graphic via Science Matters
    Cloud-seeding graphic via Science Matters

    From the Watch (Stephen Elliott):

    [Andy VanDenBerg] is one cog in a regional cloud seeding program that purports to increase wintertime snowfall over Telluride by as much as 15 percent; he’s one of the dozen or so landowners from Dolores to the southwest to Disappointment Creek and Saltado Creek further north who have allowed Durango-based Western Weather Consultants to install cloud-seeding generators on their properties, and are paid to operate them when a promising storm system moves into the area.

    “It doesn’t make much money. It’s kind of a waste of time and an inconvenience,” VanDenBerg said. “But there’s a chance it works.”

    It’s difficult — nearly impossible — to prove wintertime cloud seeding’s efficacy, but that hasn’t stopped the Telluride Ski & Golf Company, Dolores Water Conservancy District, Southwestern Water Conservation Board, Colorado Water Conservation Board, California Six Agency Committee, Central Arizona Water Conservation District, Southern Nevada Water Authority and Metropolitan Water District of Southern California from funding cloud seeding in the Upper San Miguel Drainage Basin, specifically on the Telluride Ski Resort.

    “We’re in a 15-year drought and reservoirs are down, so we’re trying to help prevent them from going down further, and maybe bring them back up a little bit,” said Bill Hasencamp, Colorado River Resources Manager for the Metropolitan Water District around Los Angeles.

    Hasencamp, like VanDenBerg, can’t be sure cloud seeding works (or at least how well it works), but his agency still enthusiastically funds the program. “There’s a general feeling that it increases snow, but no absolute proof. That’s the tough part: It’s very difficult to tell exactly,” he said.

    All of the water managers involved in the Colorado cloud seeding program cite a study from Wyoming when discussing the effectiveness of cloud seeding. The study, conducted by the National Center for Atmospheric Research and several other organizations, was completed in 2014 and compared two mountain ranges in the state: the Medicine Bow and the Sierra Madre. For 10 years, researchers randomly seeded storms in one of the ranges, but not the other, in an attempt to discover if cloud seeding increased snowfall.

    That study indicated a 5-15 percent snowfall increase, presumably due to cloud seeding.

    “There’s not really any downside to [cloud seeding],” said Joe Busto, cloud seeding program manager with the CWCB. “It doesn’t do a lot, just a few inches more here and there. It can’t replace dams or conservation; it’s just a thing we do every year and we get a little more and that’s all it is.”

    […]

    Water managers could conceivably seed clouds anywhere along the Colorado River Basin but have decided to partner with ski areas to boost recreational economies and take advantage of the funding those ski areas are willing to put up for the program.

    “Although the state supports [cloud seeding], it’s not just because we want to support all the ski areas. This is a new water source, but it has the great benefit of helping out our recreational economy in Colorado,” said April Montgomery, a San Miguel County-based representative on the CWCB. “This is also a huge benefit to Norwood and the West End. We’re producing more water for our Telluride headwater reservoir, and that’s all going down to the lower ends of the San Miguel, into the Dolores, into the Colorado.”

    As reservoirs along the Colorado River, including Lake Powell and Lake Mead, have dried up during the past few years, water managers downstream have turned to more experimental ways to keep them full, or at least less empty. Busto at the CWCB said the out-of-state agencies have contributed nearly $2 million to the Colorado cloud seeding program since 2007.

    “The reason why the state is involved in cloud seeding is because it’s the cheapest form of new water. If you look at other ways of creating new water sources, you’re looking at desalinization or you’re looking at giant reservoir systems and new diversion systems. That costs so much money,” Montgomery said. “Our snowpack is the largest reservoir we have and if we can increase our snowpack, we are basically creating this giant reservoir that we can use later.”

    […]

    But cloud seeding raises questions. Does silver iodide negatively impact the watershed once it falls out of the clouds? If we coax precipitation from clouds over Telluride, does that mean less will fall on other communities?

    Cloud seeding proponents answer a resounding “No” to both questions.

    The Wyoming study found silver concentrations in the water after cloud seeding in the parts per trillion range, and in the parts per billion range in soil, “about three orders of magnitude less than values considered hazardous to environmental system or human health.”

    “Silver iodide doesn’t dissolve into the water,” Montgomery said. “One reason I’ve been able to embrace this technology is, as we improve and we’re being more efficient and effective with it, we’re not just throwing this up into the atmosphere.”

    “This is something that doesn’t bioaccumulate,” Busto added. “When a chemical gets in the fish, then the eagles get it… That’s bioaccumulation. It’s a concern, but [silver iodide] won’t do that.”

    As for cloud seeding’s effect on nearby areas, Western Weather’s founder Larry Hjermstad, who has been working in weather modification for four decades, said seeding merely takes advantage of an opportunity in a storm.

    “One of the big concerns is, if we’re putting more precipitation in one area, it’s at the expense of another area. The answer is no; we’re creating a slightly better storm system,” he said.

    Busto added that winter storms are typically large, often 200 miles long or more, and contain huge amounts of moisture, only a small amount of which will ever fall as precipitation. So when cloud seeding urges slightly more of that moisture out of the clouds, the vast majority of a storm’s moisture remains to fall elsewhere or stick around in the cloud.

    “To say you took all the water out of a system that was 200 miles long is really a stretch,” Busto said. “Did you steal that [precipitation] from someone else? No, I don’t think so.”

    The Wyoming study concurred, finding that the “downshadow effect,” or the impact of cloud seeding on areas outside the seeded area, was negligible.

    #ColoradoRiver: Cloud-seeding supporters are hopeful efforts will fill aquifers and reservoirs — The Durango Herald

    Cloud-seeding graphic via Science Matters
    Cloud-seeding graphic via Science Matters

    From The Durango Herald (Mary Shinn):

    To seed a cloud in Southwest Colorado, employees with Western Weather Consultants light generators that send vaporized silver iodide up to the base of clouds. The silver iodide forms an artificial ice nuclei and attracts supercooled water to form snowflakes.

    In an ideal situation, the cloud would release excess water that would otherwise pass over the region, said Eric Hjermstad, co-owner and director of field operations for the company.

    “It’s meant to add just a little bit more per storm,” Busto said.

    A study in Wyoming conducted from 2005 to 2014 found cloud seeding can add 5 to 15 percent more precipitation.

    During a dry storm or a dry year it’s harder to make a difference, he said.

    Seeding during El Niño can help build snowpack to replenish aquifers and help fill reservoirs such as Lake Powell, Hjermstad said.

    It’s an investment that is supported by regional water agencies and ski resorts that paid $237,900 this season, according to the Southwestern Water Conservation District. In this area, Western Weather operates about 36 generators from Pagosa Springs to Telluride, Hjermstad said.

    This winter, the cloud-seeding supporters are looking to upgrade their efforts through better generators and potentially a radiometer that helps gauge the water and temperature of clouds before seeding, said Ken Curtis, engineer for the Dolores Water Conservancy District.

    While he said there’s always skepticism around cloud seeding, the Wyoming study showed that cloud seeding can work if the silver iodide is delivered in the right place under the right conditions.

    “We know it works, but you need to do best practices,” Curtis said.

    Last week, the Southwest Basin Roundtable granted the group about $55,600 to hire a consultant to help select equipment and the right areas to place it.

    The state will review and finalize the grant in the coming months, he said.

    The strategic plan to upgrade equipment will likely take two years because there are 12 agencies and companies involved in funding.

    #ColoradoRiver: Cloud-seeding impact to SW #Colorado

    Cloud-seeding graphic via Science Matters
    Cloud-seeding graphic via Science Matters

    From the Associated Press via The Denver Post:

    A researcher with the Colorado Water Conservation Board says cloud seeding in southwestern Colorado is helping to squeeze more water out of passing snowstorms, using heaters that vaporize silver iodide to form artificial ice.

    In southwest Colorado, workers light generators that look like large propane tanks, shooting flames into pans that send vaporized silver iodide up to the base of clouds. There, the silver iodide forms an artificial ice crystal that draws in more water, forming larger snowflakes. Then they fall to the ground.

    “When there’s lots of liquid water coming through, then you have a storm to work. The seeding response is better. You get more bang for your buck,” said Joe Busto, a researcher with the Colorado Water Conservation Board. “It’s meant to add just a little bit more per storm.”

    Researchers say a study in Wyoming conducted from 2005 to 2014 found cloud seeding can add 5 to 15 percent more precipitation.

    Eric Hjermstad, co-owner and director of field operations for Western Weather Consultants, which does cloud seeding, said every bit of water helps the parched Southwest.

    Hjermstad said seeding helps build snowpack to replenish aquifers and helps fill reservoirs such as Lake Powell for other Western states struggling to find water.

    Regional water agencies and ski resorts paid $237,900 this season to help with the seeding, according to the Southwestern Water Conservation District. Western Weather operates about 36 generators from Pagosa Springs to Telluride.

    The Southwest Basin Roundtable is providing $55,600 to hire a consultant to help select equipment and find the right areas to place it.

    Cloud-seeding gaining favor in arid West — The Durango Herald

    From the Cortez Journal (Jim Mimiaga) via The Durango Herald:

    Telluride and Purgatory ski areas contribute funds for regional cloud-seeding programs, and so do the Dolores Water Conservation District, Animas-La Plata and Southwestern Water Conservancy districts.

    During a meeting Wednesday at the DWCD office in Cortez, an update was given on the regional cloud-seeding program and ground-breaking research recently completed on the technology in Wyoming.

    “Interest in cloud seeding has grown, and funding has grown,” said Bruce Whitehead, executive director for SWCD.

    Western Weather Consultants provides cloud-seeding services for three programs in the San Juan Mountains including over the Upper Dolores, La Plata, and Animas River basins.

    From November 2014 to April 2015, 25 cloud-ice nuclei generators dispersed silver iodide into storm clouds for a total of 875 hours, at a cost of $105,678.

    The units are in the vicinity of Cortez, Dolores, Mancos, Mesa Verde, La Plata Mountains, Stoner, West Fork, Groundhog, House Creek, Placerville, Cahone, Lone Cone, Disappointment, Hesperus, Electra Lake, Bayfield, near Purgatory, on the Florida River and elsewhere.

    When dispersed in optimum storm conditions, the silver iodide enhances the formation of ice crystals in clouds, forcing more snowfall, said Mike Hjermstad, a technician with Western Weather Consultants, based in Durango.

    “The generators are turned on manually, and when the conditions are right, it can increase snow accumulation from a storm by a half inch,” he said…

    Cloud-seeding skeptics question whether the procedure actually works because it’s difficult to verify increased snowfall from cloud seeding versus what would fall naturally.

    Proponents point to experiments that show areas with cloud seeding had more precipitation compared with control areas that did not get the treatment.

    “Detection of very minute levels of silver iodide in the snowpack is also a proof,” Hjermstad said.

    Joe Busto, a cloud-seeding permit manager for the Colorado Water Conservation Board, said the environmental impacts of the silver iodide on snowpack is “very low and measured in parts per trillion above background levels.”

    He said research shows “strong suggestions of positive cloud seeding effects in winter glaciogenic systems occurring over mountainous terrain.”

    Rising costs of new technology such as radiometers, automation, and more snotels is a concern, said Ken Curtis, an engineer for DWCD.

    “The funders need to have consensus on where the program is going, if it will be enhanced or stay static,” he said.

    Barry Lawrence, of the Wyoming Water Development Office, gave a presentation on a recent groundbreaking cloud-seeding study that showed good results.

    The 10-year study cost $15 million and was funded by the Wyoming Legislature.

    The elaborate experiment positioned remote-control seeding stations in the Wind River Range and in the Medicine Bow Range.

    When winter storm conditions were ideal for seeding in both ranges, only the stations in one range were triggered on. The range without cloud seeding was the control, and then snowpack from both ranges was compared for that storm. Control ranges were alternated throughout the experiment.

    Despite some cross contamination in the controls, additional modeling and statistical analyses showed cloud-seeded ranges overall benefited from additional snowfall, Lawrence said.

    “Our independent evaluator, the National Center for Atmospheric Science in Boulder, concluded cloud seeding from the experiment resulted in 5 to 15 percent in additional precipitation,” he said.

    Encouraged by the results, the Wyoming Legislature recently approved $1.5 million to install operational cloud-seeding stations in the Medicine Bow Mountains and other ranges.

    More cloud seeding coverage here.

    Can cloud-seeding ride to the rescue? — The Mountain Town News #ColoradoRiver

    lowlakemead2012allenbest

    From The Mountain Town News (Allen Best):

    After a so-so winter, the snow piled up through May in the mountains of Colorado, taking the edge off drought. This takes the edge off of the big Colorado River reservoirs, Lake Mead and Lake Powell. But the overarching story at those reservoirs since 1999 has been of decline, even after a few big years.

    In the last several years, there has been increasing talk about the potential for the two reservoirs to become empty. Las Vegas, reliant upon Lake Mead for most of its water, isn’t just talking about the possibility. It is nigh-on to completing a third tunnel into the reservoir, this one at a cost of $817 million and, unlike the others, at the very bottom of the reservoir, in case there’s nothing left of Lake Mead except for the Colorado River. That’s how dire Las Vegas, operating as the Southern Nevada Water Authority, takes this potential of long-term drought.

    Eric Kuhn, the manager of the Colorado River Water Conservation District, spoke to the implications of this continuing drought at a forum in Colorado’s Summit County this spring. “Bad things happen when Lake Mead and Lake Powell get drained,” he said in an event covered by the Summit Daily News. He described the draining of Lake Mead as a distinct possibility in the next few years.

    What about building a pipeline to the Mississippi River or some other water-rich location? “To expect that we can export our problems to somebody else, I just don’t see that somebody else will willingly accept them,” he said.

    How about just making some more water? That effort began soon after World War II in different times of drought. Scientists at General Electric in New York state had discovered the general principle. And in some places of the West, cloud-seeding has occurred since the 1950s – including, at Vail Mountain, since 1978.

    But does it work? Since the federal government yanked research dollars from cloud-seeding experiments in the 1980s, relatively little rigorous science had been conducted. Instead, there were the claims of commercial-cloud seeders, who predicted gains of 10 to 15 percent—as long as they had clouds to work with.

    In 2004, Wyoming set out to fill that gap. An experiment that ultimately cost $14 million was designed by scientists working for a federal laboratory, the National Center for Atmospheric Research. Parallel mountain ranges southwest of Laramie, just north of the Colorado border, constituted the Wyoming laboratory. Propane was burned to loft silver iodide from ground-based generators into the clouds passing over the Sierra Nevada and Medicine Bow ranges. In the experiment, 154 storms during six winters had the temperatures needed for effective seeding, but only 118 had the moisture content. And of those, 18 were tossed out because of contamination problems.

    Slim statistical evidence

    Last December, at a meeting room in Cheyenne, scientists delivered the results. It took a full afternoon and the results were sometimes confusing. But hydrologists and meteorologists who listened to the proceedings remotely told me they had no trouble hearing the key statistics: just a 3 percent increase in precipitation but with the 28 percent probability that cloud-seeding had nothing to do with the increase. Only by creating models were researchers able to make a case that snowfall had been augmented 5 to 15 percent.

    instumentationcloudseedingresearchcolorado

    Taking stock of this and other winter weather-modification studies, the Bureau of Reclamation was unimpressed. “As such,” said the agency in a draft analysis released in February, “the ‘proof’ the scientific community has been seeking for many decades is still not in hand.”

    Proof in science requires a 95 percent probability of causality. This is extremely difficult to achieve in complex atmospheric processes, whether cloud-seeding or many of the processes involved with a warming global climate.

    In Wyoming, elected officials have decided the evidence to support cloud-seeding is strong enough to justify additional investments in various drainages—including the Wind River Range, which produces water for a tributary of the Colorado River—even as they have been loathe to admit the science of global warming.

    Wyoming isn’t alone. Water agencies and cities from Denver to Los Angeles pay for seeding clouds in the mountains of Colorado and Wyoming, and representatives heard what they wanted to hear.

    “It’s good evidence that it works,” said David Cole, who administers weather-modification programs for the Utah Division of Water Resources.

    “There is always that question, ‘Can you prove it beyond a shadow of a doubt?’” he added.

    From Los Angeles comes a similar appraisal of confirmation. “These results are consistent with historic studies,” said Tom Ryan, of Metropolitan Water District of Southern California, a consortium of agencies that collectively serves 18 million people.

    I heard similar remarks from the Central Arizona Project, which uses a 336-mile-long system of aqueducts, tunnels, pumping plants, and pipelines to deliver water to Phoenix, Tucson, and cotton farms and golf courses along the way.

    Along with Las Vegas, Arizona and California chip in to pay for cloud-seeding in Colorado and Wyoming.

    Dan Breed, project scientist with NCAR, said that failing to achieve a 95 percent confidence level in results is not unusual in cloud-seeding studies. The fundamental problem, he says, is the complexity of atmospheric processes.

    It’s the same challenge that has prevented most climate scientists from linking specific weather events, such as the September 2013 floods in Colorado, to rising global temperatures and the 3 to 5 percent observed increase in atmospheric moisture related to that warming.

    “When it comes to the atmosphere, there are just too many variables, and that variability just keeps rearing its ugly head when it comes to cloud-seeding,” says Breed. “Even in this case, where we tried to make things as homogeneous as possible to reduce that variability, variability still kind of hurt us.”

    Breed thinks research might better be invested in understanding specific atmospheric processes of wind, temperature, and precipitation. For example, how likely is it that silver iodide or other seeding agents released from the ground will get into the clouds?

    Understandings of atmospheric processes, says Breed, has mostly come from observations, instead of experiments – because of that same variability.

    This lack of certainty does not necessarily kill the prospects of cloud-seeding, as is demonstrated by the continued interest of Wyoming legislators in funding cloud-seeding.

    Cloud-seeding to the rescue?

    Can cloud-seeding the answer to the problems of California, now in its fourth year of drought, or of the Colorado River?

    The river is notoriously strapped to meet all of the wants and maybe even the needs. River flows have declined 20 percent in the 21st century as compared to the last century.

    Breed disputes conclusions that cloud-seeding doesn’t necessarily work. But he doesn’t see it as a game-changer for the Colorado River. Modifying the weather is a fairly straightforward, quick and inexpensive way to produce more water, but the gains are marginal. “It is not, he says, a magic bullet. “It won’t solve the problem.”

    In his appearance in Summit County, Kuhn took a broad view, describing the 21st century as a time of transition. “After 100 years of develop more, develop more, develop more, we’re going to have to cut back our uses.”

    That’s the difficult conversation now underway in California as residents in places like San Jose argue about lawn sizes and almond groves. It’s also the more earnest conversation that, despite the extraordinary rains in May, is getting underway in Colorado.

    More cloud seeding coverage here.

    Wyoming’s 10 year cloud-seeding experiment scrutinized

    Cloud-seeding graphic via Science Matters
    Cloud-seeding graphic via Science Matters

    From the East Oregonian (Allen Best):

    Wyoming just spent $14 million and the better part of 10 years on a rigorous scientific experiment to evaluate whether it’s possible to get extra snow from winter storm clouds through cloud seeding. The conclusion? The final results were thin: There was a 3 percent increase in precipitation, but a 28 percent probability that the cloud seeding had nothing to do with it.

    Given the results of this and other winter weather-modification studies, the Bureau of Reclamation remains unimpressed. “As such,” said the agency in a draft analysis released in February, “the ‘proof’ the scientific community has been seeking for many decades is still not in hand.”

    Proof in science requires a 95 percent probability of causality. But this standard is extremely difficult to achieve in complex atmospheric processes. Climate scientists, for example, mostly resort to asterisk-laden words such as “likely” to indicate lower levels of probability…

    From the start, Wyoming’s cloud-seeding experiment was designed to ensure scientific rigor. Parallel mountain ranges southwest of Laramie, just north of the Colorado border, constituted the Wyoming laboratory. Propane was burned to loft silver iodide from ground-based generators into the clouds passing over the Sierra Nevada and Medicine Bow ranges. In the experiment, 154 storms during six winters had the temperatures needed for effective seeding, but only 118 developed adequate moisture content. And of those, 18 were tossed out because of contamination problems.

    Dan Breed, project scientist with the National Center for Atmospheric Research, which designed and oversaw the Wyoming experiment, said that failing to achieve a 95 percent confidence level in results is not unusual in cloud seeding studies. The fundamental problem, he says, involves the difficulty of measuring atmospheric processes.

    The challenge inherent in the complexity of the data has prevented most climate scientists from directly linking specific weather events, such as the September 2013 floods in Colorado, to rising global temperatures, or even to the 3 to 5 percent observed moisture in the global atmosphere.

    “When it comes to the atmosphere, there are just too many variables, and that variability just keeps rearing its ugly head when it comes to cloud seeding,” says Breed. “Even in this case, where we tried to make things as homogeneous as possible to reduce that variability, variability still kind of hurt us.”

    Breed thinks research might better be invested in understanding the interaction in the atmosphere of wind, temperature and precipitation. For example, how likely is it that silver iodide or other seeding agents released from the ground will get into the clouds? True understanding of atmospheric processes, says Breed, has mostly come from observations instead of experiments — because of that same variability.

    This lack of certainty does not necessarily kill the prospects of cloud seeding, as is demonstrated by the continued interest of Wyoming legislators in funding projects. In the Colorado River Basin, cities and water districts seized upon the modeled projections of 5 to 15 percent snowpack augmentation as justification for continued or even expanded operations. Already, metropolitan Los Angeles, the Central Arizona Project and the Southern Nevada Water Authority, among others, pay for seeding clouds in Colorado, the source of half the water in the Colorado River, and last year they also paid to seed clouds in Wyoming, in the Green River drainage.

    More cloud seeding coverage here.

    Wyoming reconsiders cloud seeding and potential benefits for ag

    More cloud seeding coverage here.

    Cloud seeding study boosts hopes in parched West — WyoFile

    Cloud-seeding graphic via Science Matters
    Cloud-seeding graphic via Science Matters

    From Environment & Energy Daily (Annie Snider) via WyoFile:

    As a painful reckoning sets in throughout the West, where the Colorado River Basin is in its 15th straight year of drought, desperate water managers are welcoming a new cloud-seeding study as rare good news.

    The concept of cloud seeding — using aircraft or ground-based generators to inject microscopic particles of silver iodide into clouds around which ice crystals can form and fall as snow — dates back to the 1940s.

    Today, ski resorts, water districts and farmers across the West swear by the practice to produce both snow and water, spending millions of dollars a year on machines and flights.

    But proving that money is well-spent has been tricky. Because, while it might snow or rain after a cloud’s been seeded, it’s hard to know whether the seeding actually caused the precipitation…

    Wyoming’s Legislature took the challenge and, buoyed by coffers filled from oil and gas severance taxes, poured $14 million into a major study over the past 10 years that employs the latest scientific techniques recommended by the NRC panel, as well as an independent evaluation team.

    The topline findings, recently unveiled to the Legislature: Seeding the right storms the right way can produce 5 to 15 percent more precipitation. That could increase streamflows by as much as 3.7 percent, the researchers’ initial findings indicate.

    The study also found seeding to have next to no downwind impact, suggesting seeding storms to get precipitation in one place is not decreasing precipitation elsewhere.

    “We know that silver iodide produces ice crystals, so really it ends up being an engineering problem: Can the ice crystals get into the right cloud at the right place and can we do all this?” said Roy Rasmussen, a senior scientist with the National Center for Atmospheric Research who led the study’s outside evaluation team.

    “That’s what the Wyoming program demonstrated: That, yes, they can do it,” he said. “With modern technologies — through satellite-controlled silver iodide generators, and with good forecasting, with good real-time modeling — we can figure out when the storms are right for seeding and apply the seeding, and there is a measurable effect.”

    More cloud seeding coverage here.

    Water Lines: Cloud seeding can work, but it won’t fill Lake Powell — Grand Junction Free Press

    Cloud-seeding graphic via Science Matters
    Cloud-seeding graphic via Science Matters

    From the Grand Junction Free Press (Hannah Holm):

    In the arid West, the perpetual search for new water supplies, like the mythical search for the Holy Grail, has given rise to numerous fantastical adventures and grand schemes. Some of these have resulted in the impressive feats of engineering that have re-plumbed much of the Colorado River Basin, and some have remained fantasies, like towing ice bergs from the Arctic and building pipelines from the Great Lakes.

    “Cloud seeding” to wring more moisture from the sky has long been hard to classify in those terms. Water agencies and ski resorts have been doing it for decades, mostly by sending plumes of silver iodide from ground-based burners into likely-looking clouds. Cloud seeding has been done in Colorado since the 1950s and ramped up significantly after the 2002 drought. Still, until recently, no one could say with any certainty if cloud seeding really worked, or if so how well.

    Draft conclusions from a much-anticipated, very rigorous nine-year study conducted in Wyoming indicate that cloud seeding can, in fact, increase the water yield from some storms, but the ultimate effect on the water supply is quite modest. The draft executive summary of the Wyoming Weather Modification Pilot Program study, conducted by numerous collaborators, was presented to the Wyoming Water Development Commission on Dec. 10; it is due to be finalized in March of 2015.

    The study combined physical, modeling and statistical studies of the effects of cloud seeding in Wyoming’s Medicine Bow, Sierra Madre and Wind River Ranges and concluded that seeding could increase snow accumulations from some storms by 5-15 percent. This does not, however, translate to a 5-15 percent increase in the seasonal snowpack because not all storms are “seedable,” and those that are cover only a limited area.

    In order for the inserted silver iodide to stimulate significant additional snowfall, atmospheric temperatures must be below 17 degrees Fahrenheit, with sufficient moisture in the air and favorable winds. These conditions were met less than one-third of the time during the winter in the study area. Using modeling, the study concluded that increased precipitation from seeded storms of 5-15 percent affecting 30-80 percent of the cloud-seeding impact area could increase streamflow in Wyoming’s portion of the North Platte River Basin between 0.4 to 3.7 percent.

    Depending on numerous factors related to the operations of the cloud seeding program, the cost-per-acre-foot of water produced through cloud seeding ranges from $27-$427 per acre-foot. This compares favorably with other options for producing “new water.” In a 2013 article in the Mountain Town News, Allen Best reports that the Bureau of Reclamation has estimated that desalting brackish groundwater in Arizona would cost $650 per acre-foot, and desalting ocean water near Los Angeles would cost $2,100 per acre-foot. Cost estimates for building new storage reservoirs run from a few hundred dollars per acre-foot to over $1,000 per acre-foot.

    In addition to assessing the potential impact of cloud seeding as a feasible strategy for impacting Wyoming water supplies, the study also assessed the environmental impacts of seeding and impacts on precipitation outside the seeded area (i.e. does it steal water from downwinders?).

    The environmental analysis found that concentrations of silver iodide in the affected snowpack was in the parts per trillion range, while concentrations already in the soil were much higher, in the parts per billion range, indicating a very minimal impact from cloud seeding. Modeling of impacts on precipitation outside the seeded area indicated effects of less than 0.5 percent, which is consistent with previous studies and undermines claims that cloud seeding injures those downwind of seeded areas.

    This study indicates that cloud seeding likely deserves its relatively newfound respectability as a water supply strategy, but also that its impacts are far too small for it to be a panacea for the West’s water woes.

    To read the draft executive summary for yourself, go to the Wyoming Water Development Commission’s website at http://wwdc.state.wy.us.

    More cloud seeding coverage here.

    Report: Wyoming cloud seeding program said to increase snowpack

    wyomingweathermodificationpilotprogramexecsummaryfinaldraft12102014

    Click here to read the draft executive summary. Here’s an excerpt:

    The Wyoming Weather Modification Pilot Program (WWMPP) was conducted to assess the feasibility of increasing Wyoming water supplies through winter orographic cloud seeding. Following a Level II feasibility study that found considerable potential for cloud seeding in the state (WMI 2005), the Wyoming Water Development Commission (WWDC) funded the WWMPP (2005-2014) as a research project to determine whether seeding in Wyoming is a viable technology to augment existing water supplies, and if so, by how much, and at what cost. The WWMPP then established orographic cloud- seeding research programs in three Wyoming mountain ranges considered to have significant potential: the Medicine Bow, Sierra Madre, and Wind River Ranges…

    Orographic cloud seeding is a technology designed to enhance precipitation in winter storms with an inefficient precipitation process due to a lack of natural ice nuclei. This inefficiency allows supercooled water to persist for long periods instead of being depleted by ice crystals, which grow and fall as snow. This fact is well documented by the measurement of sustained supercooled liquid water in orographic clouds taken by aircraft and ground-based instruments, such as radiometers. In contrast to natural ice nuclei, artificial ice nuclei, such as silver iodide, will nucleate substantial numbers of ice crystals at subfreezing temperatures of −8 °C (+17 °F) and cooler, creating ice crystals in clouds that are typically too warm for natural ice formation. In the presence of supercooled water droplets, these ice crystals rapidly grow into larger particles that fall to the ground as snow. The technology of orographic cloud seeding uses ground-based generators to produce a silver iodide plume, which is then transported by the ambient wind into orographic clouds to increase precipitation. This process of seeding clouds to create additional snow is complex and to date has not been scientifically verified in well-designed statistical tests.

    More cloud seeding coverage here.

    Results from Wyoming’s cloud-seeding efforts expected next month #ColoradoRiver

    Cloud-seeding graphic via Science Matters
    Cloud-seeding graphic via Science Matters

    From the Casper Journal (Greg Fladager):

    Wyoming’s $13 million cloud seeding experiment may be about to pay off, or at least further knowledge in the science of rainmaking.

    In a talk to the Wyoming Water Association last month, Wyoming Water Development Commission Director Harry LaBonde, Jr., said the results of over eight years of study would finally be released this December.

    “All I will tell you about the results is that it appears that it is positive,” LaBonde told the group in Casper. “Of course what we want to know is, what can you anticipate with winter orographic seeding? Is that a 2 percent increase in precipitation? Is that a 10 percent increase in precipitation, or what can you expect?”

    Broad interest

    LaBonde said Wyoming’s experiment has drawn regional as well as international attention.

    “Everybody wants an answer to the question that we have been asking, and so you are going to see a lot of interest. It will then hopefully be considered and utilized in other states across the West, as well as other operations across the world,” LaBonde said.

    The cloud seeding program was conducted in the Medicine Bow/Sierra Madre Mountain Range in southern Wyoming. The study was based on eight snow generators placed in two closely related areas, and in double blind experiments data gatherers were not told which valley had been seeded for a given seeding event.

    “The last data collection was last spring. It ended in April, representing about eight years of data collection,” LaBonde said. “We went through some drought years which limited seed-able events. But last year was a very good year. We had about 30 seeding events last year. We ended up with a total of about 160 events over the period of time. That was determined to be a suitable amount of events that … we can make a good scientific conclusion of does weather modification work? Is there an increase in precipitation when you are seeding these mountains with silver iodide, which is the product that we have been using.”

    “So, with that data complete, the scientists have been poring over that — we certainly have issues with data quality and some of that, they’ve been looking at all of those issues — but what we hope to have, and what is on the schedule now, is their final report by December of this year,” LaBonde added. “It is our hope that in fact that schedule will be kept, and that document will become public information.”

    Wyoming Range and Wind River seeding projects

    In the meantime, Wyoming has two other cloud seeding experiments and operations.

    “Another weather mod item in Wyoming is that we funded, last year, a Level II weather modification study in the Wyoming Range,” LaBonde said. “I think a lot of you know that Idaho Power runs a very active weather modification (program) out of the Star Valley, and some (of those) seeding effects do roll over into the Wyoming Range. But we wanted to take a more thorough look at what we might be able to do if we are going to set up an operational program in the Wyoming Range. Where might you site those generators? What kind of benefits would accrue to the Colorado River drainage on the East slope of those mountains, as well as the Snake River on the backside (and) the West side of those mountain ranges? So that study is underway. We expect to have the results of that next summer. That was the continuation of what was in essence a Level I study that was started in 2008, completed and then put on the shelf pending the outcome of our scientific programs.”

    Moving from study to operations

    LaBonde also announced that the WWDC was successful in its effort to get funding to continue cloud seeding in the Wind River Range, and changing (operations) from a scientific study to an operational program.

    “The proposal that Water Development put forth to the legislature last year was that we wanted to keep those 10 generators in operation. We wanted to shift from scientific to an operational mode,” LaBonde explained. “However, we did not feel that all of the costs should be borne by the state of Wyoming. The Green River has not appropriated water. Those waters flow out-of-state, and ultimately benefit the lower basin states. So the proposal that was put forth is that Wyoming would pay for 25 percent of the cost of the operation of those generators, but we were required to go forward and seek funding partners from other states to pay for 75 percent of the program.”

    Funding buckets

    “I’m happy to report today that, in fact, we have achieved the outside funding sources that were required as part of that bill, as a result we will have an operational seeding program run in the Wind Rivers this year,” LaBonde said.

    “The funding partners that we’ve put together are: the Arizona Department of Water Resources; Central Arizona Water Conservation District: the Six Agency Committee, which is a group of agencies in California; Southern Nevada Water Authority; Utah Division of Water Resources — of course the Green River flows into Utah, and I think that was a little bit of a surprise that they came forward and wanted to help with the funding; the Bureau of Reclamation has stepped up and it is funding, in essence, the forecasting part of our programs. They’ve got a direct contract with NCAR (National Center for Atmospheric Research), and that outside funding source is $684,000. The respective Wyoming share is $28,000. There will be seeding in the Wind Rivers again, subject to appropriate storms coming across. We’ll start in November, and run into the April season, LaBonde said.”

    Augmenting water

    LaBonde further noted that he viewed the Wind River Range project as a first step in ‘water augmentation’ in the Colorado River Basin.

    “With the ongoing drought in the Colorado River Basin — we have dropping lake levels in Powell and Mead — we thought that maybe, even though we did not have the results of the scientific study, it was appropriate to look at continuing those generators, but moving from a scientific to an operational program.”

    “Colorado has a weather modification program. So does Utah. But how do we bring the lower basin states into that program?” LaBonde continued. “I know there are some committees that have been formed, they are talking about that. But with 10 generators in place last year, it was too good an opportunity to go forward — at least for a one-year program — and we, again my hope is, it is going to morph into a more basin wide program.”

    LaBonde concluded he was optimistic about cloud seeding expanding to other mountain ranges in the state.

    “All in all, I think it’s good news,” LaBonde said. “Finally, there’s some pieces that are going to fall into place with our scientific study coming out. Then hopefully we will see some more operational programs going forward in the future.”

    More cloud-seeding coverage here and here.

    Radiometer near Mancos used to forecast cloud-seeding potential

    Calibrating the radiometer via The Durango Herald
    Calibrating the radiometer via The Durango Herald

    From The Durango Herald (Mary Shinn):

    On Monday meteorologist, Marta Nelson, installed a temporary radiometer at Jackson Lake near the Mancos Water Conservancy District. The instrument is able to determine the best combination of water content in clouds and temperature to use a cloud-seeding generator.

    Cloud-seeding generators throw up silver iodide into the atmosphere to harvest the extra water because snow will form around it.

    “We can see relative humidity and vapor and the potential for a cloud to form. We can also see inside a cloud that’s already formed, so if we’re looking for liquid water versus ice that is frozen in the cloud the radiometer can tell the difference and help tell the cloud-seeding people when to run the generators or when it’s not going to do any good,” she said. Nelson works for Radiometrics Corp., based in Boulder, which installs similar machines all over the world.

    The new data also will help scientists decide if the local cloud-seeding generator at Spring Creek should be run later into the winter season, said Jeff Tilley, director of weather modification at the Desert Research Institute in Reno. The institute operates the local cloud-seeding generator remotely. The data collected over the next month will be applied to operations next winter because the Spring Creek generator is almost out of cloud-seeding solution, he said.

    The institute is collaborating with the Colorado Water Conservation Board on the project, and the board is paying the $8,500 to lease the radiometer for a month.

    Across the state, about $1 million is spent on cloud seeding, and about 65 percent of the funds are provided by local entities such as ski areas, water districts and towns. The other 35 percent of the funds are provided by state and other funding.

    The generator near Mancos has been in place for about five years, and in that time, there has been some benefit in the area, Tilley said.

    “The impression we have is that we have seen some difference,” he said.

    Cloud seeding is safe because silver iodide won’t break down in any way that’s harmful, Nelson said.

    More cloud-seeding coverage here. More San Juan River Basin coverage here.

    Ski areas, et. al, kick off this winter’s cloud-seeding program

    Cloud-seeding graphic via Science Matters
    Cloud-seeding graphic via Science Matters

    From the Colorado Independent (Bob Berwyn):

    In Colorado, ski-area operators and water managers have been known to do a few rain dances and — privately at least — pray to their own God when drought strikes. But in the age of technology and hubris, when nearly every challenge is met with engineering, they aren’t just waiting for Mother Nature to put her cards on the table. Instead, there’s a growing interest in seeding clouds with silver iodide to coax every possible bit of moisture from passing storms.

    Weather modification has historic roots in the Cold War era, when both the U.S. and Soviets looked at ways to weaponize weather, and more recently, U.S. intelligence agencies decided to help fund a far-reaching study aimed at determining if there’s a way to mitigate global warming with technology and engineering.

    Proponents have claimed for years that seeding can increase snowfall in targeted areas by as much as 15 percent. As a result, water providers like Denver Water, and big ski resorts, including Vail, Breckenridge and Winter Park, are all helping fund a $1 million cloud-seeding program in Colorado’s north-central mountains, hoping to improve ski conditions, as well as boost stream flows and reservoir storage.

    Recent news about record-low flows from Lake Powell, the key Colorado River reservoir, has spurred even more interest in enhancing natural precipitation, said one of the state officials who manages what’s formally called a weather modification program. A roster of companies involved in cloud seeding and related activities shows that weather modification is a growth industry.

    The state program is run by the Colorado Water Conservation Board, which issues permits and sets basic rules — for example cloud-seeding stops when the snowpack reaches a certain level to address concerns about avalanches and flooding.

    But those rules haven’t quelled concerns, as there are still a few people left who probably think that tinkering with the weather on a large scale is probably one of the worst ideas ever. Those sentiments were reflected during a hearing for cloud seeding permits in the early 2000s. Residents of Evergreen turned up en masse to claim that, ever since Vail started seeding clouds (way back in the 1980s), snowfall in their town has declined.

    The CWCB program was jump-started with state seed money in the early 1970s, but since then has become 80 percent – 90 percent self-funded through grants and participation by resorts and water providers, with everyone seeing cloud-seeding as a low-cost alternative to building new reservoirs and pipelines. And with an uncertain outlook for Colorado River flows, even downstream states like Arizona and California are ponying up to help pay for cloud seeding in the headwaters.

    The question about downwind impacts seems reasonable. After all, there’s only so much moisture in every cloud. But weather experts like Colorado state climatologist Nolan Doesken say there’s not a shred of evidence to show that cloud-seeding affects snow and rainfall downwind of the specific target areas. The weather pattern most suitable for mountain cloud seeding (a steady, moisture-laden jet stream out of the northwest) generally leave the plains high and dry.

    On the other hand, Doesken said there’s no clear evidence to show that seeding enhances snowfall anywhere near the amount claimed.

    “If it really increased snowfall by 15 percent, you’d be able to see that in streamflow records from, say, the Gunnison Basin (where seeding has been ongoing for many years), but that’s not the case,” Doesken said. Overall, he believes that seeding does boost precipitation, but by a lesser amount than claimed…

    So when your score your first face shots this coming winter, go ahead and enjoy the celebratory bonfire in honor of Ullr, the Norse god of skiing. But just to be on the safe side, don’t forget to raise your glass in a toast the men and women who promise better living — including more snow — through chemistry and engineering.

    More cloud-seeding coverage here and here.

    Cloud-seeding program for the central mountains for this season ended on April 10 #COdrought #ColoradoRiver

    cloudseedingexplained.jpg

    From the Summit County Citizens Voice (Bob Berwyn):

    While the winter’s biggest snow totals came after the end of this year’s program, the seeding operations may have helped bring near-average snowfall to area in February and March, according to the operators, who are now measuring their efforts under a “target and control” evaluation that will be submitted to the Colorado Water Conservation Board for review.

    Durango-based Western Weather Consultants, which seeds the central mountains, was able to extend operations into early April and use all its allotted operational days, said Larry Hjermstad. During the 2012-2013 season, the central mountains program cost $293,600 and targeted an area of about 1,668 square miles of the Upper Colorado River Basin, generally above elevation 8,500 feet, in parts of Pitkin, Eagle, Summit, and Grand counties. Front Range water providers and ski areas, along with other partners, help fund the program, aimed at enhancing water supplies and boosting ski conditions at A-Basin, Breckenridge, Keystone and Winter Park, all included in the target area…

    In past seasons, Hjermstad estimated that cloud-seeding may have boosted snowfall by as much as 15 percent in targeted areas.

    Cloud-seeding efforts in Colorado have a long, on-and-off history dating back to the 1970s, when the federal Bureau of Reclamation was active in the southwestern mountains, said state climatologist Nolan Doesken, who acknowledged that there is still a debate about the effectiveness of cloud-seeding. Doesken said that there is good evidence that cloud-seeding can work in the right conditions, with very specific requirements as to wind direction, moisture and temperatures. Outside that range, the results are less clear.

    Funding comes from the Front Range Water Council including Aurora Water, Denver Water, Colorado Springs Utilities, Northern Colorado Water Conservancy District, Twin Lakes Reservoir & Canal Company, Southeastern Colorado Water Conservancy District, and Pueblo Board of Water Works. The Colorado River Water Conservation District, A-Basin, Keystone, Breckenridge, and Winter Park also participate.

    The Colorado Water Conservation Board and the Lower Basin States, including the Southern Nevada Water Authority, Central Arizona Water Conservation District, and California Six Agency Committee also help fund the cloud-seeding, but don’t directly participate in the program, said program manager Maria Pastore, of Glenwood Springs-based Grand River Consulting.

    More cloud-seeding coverage here and here.

    Grand Mesa cloud-seeding program history and results #ColoradoRiver

    Cloud-seeding graphic via Science Matters

    From the Grand Junction Free Press (Sharon Sullivan):

    For 50 years, humans have attempted to modify the weather for the purpose of increasing snowpack, to fill up reservoirs, reduce hail, and even prevent rain. The scientific practice of cloud seeding has been utilized on Grand Mesa since the 1990s. Two years ago, the Water Enhancement Authority stepped up its Grand Mesa program by doubling the number of cloud seeders to 16. “We’re trying to increase snowpack on the Mesa, to fill up the reservoirs,” said Mark Ritterbush, the Grand Junction water operations supervisor and secretary for the Water Enhancement Authority (WEA).

    The WEA is comprised of the City of Grand Junction, Powderhorn Ski Mountain Resort, Collbran, the Grand Mesa Water Conservancy District, and Overland Ditch and Reservoir Company. Funding for the cloud-seeding program comes from those entities, as well as Delta County, the Colorado River District, the Colorado Water Conservation Board and lower Colorado River basin states.

    Meteorologists determine where to place the cloud-seeding machines on the Mesa. Oftentimes, they’re located on private property where landowners are paid rent to host the machines.

    In China, cloud seeders — many of them farmers — are paid to use anti-aircraft guns and rocket launchers to release pellets containing silver iodide into clouds, according to Wikipedia. Other areas disperse the precipitation-enhancing agents via airplanes.

    On the Grand Mesa, cloud-seeding machines consist of tanks on the ground filled with a silver-iodide solution containing chemicals such as acetone. The solution is sprayed across a propane-fueled flame, causing the particles to drift with the wind current up into the cloud. The condensation nuclei turn into ice crystals, ride along with the cloud and fall out as a snowflake. Silver iodide is used because its crystalline structure is almost identical to ice, Ritterbush said.

    “A meteorologist (John Thompson of Montrose) watches storms as they come in,” Ritterbush said. “He calls and tells (the landowners) when to turn it on. Rarely are all 16 cloud seeders running at the same time.”

    IS CLOUD-SEEDING EFFECTIVE?

    There is an ongoing debate regarding the effectiveness of cloud seeding versus letting nature take its course, Ritterbush said. Ten years ago, the National Academies of Science released a report saying, that after 30 years of research, there is no convincing proof of intentional weather modification efforts. “In nature, it’s hard to set up an experiment with a control,” Ritterbush said. “It’s a conundrum how to compare.”

    Yet, studies suggest cloud seeding can increase snowpack 5 to 15 percent, which makes the program’s annual cost of between $30,000 and $40,000 cost-effective when you factor in the extra water, Ritterbush said. The cost variable is due to weather conditions, how often seeding takes place, and the cost of silver, Ritterbush said. According to the World Meteorological Policy Statement, “a well-designed, well-executed program shows demonstrative results,” said Joe Busto, who runs the weather modification permitting program out of Denver for the Colorado Water Conservation Board.

    The Grand Mesa has been a forum to introduce new equipment and different seeding technologies, Busto said. The topography is ideal for setting up cloud-seeding machines at a high elevation, he said. “There’s a rich history of research on the Grand Mesa, during the ’70s, ’80s, and ’90s,” Busto added.

    Arlen Huggins, a semi-retired research scientist with the Desert Research Institute in Reno, Nev., is familiar with the Grand Mesa project. Huggins said there is plenty of convincing evidence that modifying weather is effective for increasing precipitation. He mentioned prior Bureau of Reclamation studies, plus a recently completed five-year experiment in Australia. “There’s a lot of evidence related to snowfall enhancement,” Huggins said. “It makes it a viable option for increasing water supply.”

    The Water Enhancement Authority is in the process of collecting data comparing seeded areas versus non-seeded areas on the Mesa, Ritterbush said.

    ENVIRONMENTAL RISKS?

    So, what happens when silver-iodide particles hit the ground or land in lakes or rivers? While there has been no monitoring for silver in western Colorado’s environment, researchers in Australia have spent millions searching for traces of the mineral, Ritterbush said. In Australia, where lake beds and soils have been tested, they “just don’t find it near toxic levels,” Busto said.

    Huggins, who is considered a cloud-seeding expert, said he’s often asked about potential risks of silver toxicity in the environment. “It’s a minuscule amount of silver being released,” Huggins said. “The silver iodide amounts released are not harmful. (The particles) are not soluble in water. It cannot be taken up by aquatic species. It does not bio-accumulate.”

    There are approximately 106 cloud-seeding sites in Colorado, including Summit County, Gunnison, Telluride and the Dolores area, the West and Eastern San Juan mountains. Vail and Beaver Creek have the oldest program, having cloud-seeded for 38 years. Most permits are issued from November through March and sometimes into mid-April, Busto said. “We monitor snowpack, avalanche hazards, and suspend programs when needed,” he said.

    A 2010 statement from the American Meteorological Society states that “unintended consequences of cloud-seeding, such as changes in precipitation or other environmental impacts downwind of a target area have not been clearly demonstrated, but neither can they be ruled out. Continued effort is needed toward improved understanding of the risks and benefits of planned modification through well-designed and well-supported research programs.”

    More cloud-seeding coverage here and here.

    Cloud-seeding rules may help to determine the efficacy of the various delivery methods #CORiver

    cloudseedingexplained.jpg

    From the Summit County Citizens Voice (Bob Berwyn):

    As part of the state-authorized weather modification plan, operators of cloud-seeding operations are required to complete annual “target versus control” analyses, comparing snowfall in target areas against similar non-targeted control areas. Over time, the data from those evaluations may help determine if cloud seeding really does boost snowfall by up to 15 percent, as claimed by the operators.

    “This method is credible and develops relationships between snow data and tracks precipitation totals over time in both seeded areas and non-seeded areas to help track the efficacy of the program,” said Maria Pastore, of Glenwood Springs-based Grand River Consulting, who manages the central mountains cloud-seeding rogram.

    “In addition, the State has new data types and evaluation methods suggested for cloud seeding programs,” Pastore said. “They are not required but are suggested as good periodic evaluations that can help the long-term sustainability of these programs.”

    Cloud seeding in Colorado involves burning silver iodide in ground-based generators to inject tiny particles of the material into approaching weather systems. The silver iodide is said to provide nucleii for crystal formation and growth, helping to wring a bit of additional moisture from the clouds.

    For the 2012-2013 season, the central mountains program will cost $293,600 and target an area of about 1,668 square miles of the Upper Colorado River Basin, generally above elevation 8,500 feet, in parts of Pitkin, Eagle, Summit, and Grand counties. If it works, the program could benefit A-Basin, Breckenridge, Keystone and Winter Park, all included in the target area.

    More cloud-seeding coverage here and here.

    Drought news: Public hearing tonight for Western Weather Consultants’ cloud-seeding application

    cloudseedingexplained.jpg

    Here’s the notice from the CWCB website:

    The CWCB has received an application from Western Weather Consultants to renew their permit for a wintertime ground based cloud seeding program on behalf of Denver Water and Colorado Springs Utilities and several other sponsors.

    This notice of intent has been advertised in eighteen newspapers in eighteen counties for this public hearing.

    The public hearing will be held at La Quinta Inn & Suites, Loveland Room, 560 Silverthorne Lane, Silverthorne, Colorado, at 6:00 PM on Monday September 24, 2012.

    The public record will be held open so that comments can be emailed to joe.busto@state.co.us or mailed with postmark of October 1, 2012 for consideration as part of the record of decision.

    Public comments oral and written are used by the State to develop a record of decision that is used to deny, approve, or approve with special terms and conditions a weather modification permit.

    More CWCB coverage here.

    Gunnison County files application to continue cloud seeding program for another ten years

    cloudseedingexplained.jpg

    From The Chaffee County Times (Casey Kelly):

    North American Weather Consultants has filed an application with the Colorado Water Conservation Board for a 10-year renewal of its cloud seeding program in Gunnison. According to the group, Chaffee County could benefit from additional water from the program.

    Since 1950, NAWC has been conducting weather modification programs in the western United States and has been cloud seeding in the Gunnison area for the past 10 years. The purpose of the operation is to increase precipitation and snowpack in the area for agriculture, municipal water, recreation and tourism.

    Current cloud seeding programs in Colorado:

    Central Colorado Rocky Mountains Program (Denver Water and Winter Park)
    Upper Roaring Fork Basin Program (Colorado Springs Utilities)
    Vail/Beaver Creek Program (Vail/Beaver Creek Ski Areas)
    Gunnison River Basin Program (Gunnison County, Upper Gunnison River WCD)
    Grand Mesa (Water Enhancement Authority which is comprised of Collbran WCD, Fruitland Mesa WCD, Crawford WCD, Grand Mesa Pool)
    Western San Juan Mountains Program (Southwestern WCD, City of Durango, Animas La Plata WCD, Durango Mountain Resort, Dolores WCD)
    Eastern San Juan Mountains Program (Pagosa Area Water and Sanitation District, San Juan WCD, Southwestern WCD)

    More cloud seeding coverage here and here.

    Cloud seeding: Applied science or alchemy?

    cloudseedingexplained.jpg

    From the High Country News’ Goat blog (Emily Guerin):

    Making rain may seem a bit like alchemy, but the practice has been around since the 1940s, when engineers at General Electric began experimenting with dumping dry ice into clouds from airplanes. Water districts and ski resorts around the West got into the practice in the 1970s, shooting silver iodide into winter clouds from mountain-top cannons…

    Silver iodide crystals behave like ice, attracting water droplets to them until they grow big enough to fall to the ground as snow. Cloud seeding advocates say the practice is inexpensive—$10-20 per acre-foot of water created—and can boost snowfall by 10 to 15 percent. They’re also quick to point out there are no documented negative environmental effects of the process.

    But it’s hard to separate cloud seeding-induced precipitation from what falls naturally from the sky. A 2010 study by Israeli researchers examining rainfall patterns and cloud seeding over the Sea of Galilee in Northern Israel found that a series of cyclones were responsible for increased rainfall over a six-year period, not cloud seeding. The state of Wyoming is currently spending $11 million on a multi-year study to determine whether the practice works and is cost-effective. Results are expected in 2014.

    Still, the science is apparently convincing enough for water districts in Southern California, Nevada and Arizona to pay Upper Colorado River Basin states to seed clouds. Since 2006, Lower Basin states have spent over $800,000 in Colorado and around $500,000 in Utah and Wyoming.

    More cloud seeding coverage here and here.

    Delta County chips in some dough for the Grand Mesa cloud-seeding effort this year

    cloudseedingexplained.jpg

    From the Delta County Independent (Hank Lohmeyer):

    A multi-agency supported cloud seeding project on the Grand Mesa is in line to receive $1,000 in support from the Delta County Commissioners next year [2012]…

    The multi-agency Water Enhancement Authority “is a non-profit organization of three water conservancy organizations,” explained WEA secretary treasurer Mark Ritterbush in a letter to the commissioners. The three agencies are the Grand Mesa Water Conservancy District, the Grand Mesa Water Users Association, and the Collbran Water Conservancy District. The three districts, along with other regional government bodies, donate to the Water Enhancement Authority.

    According to Ritterbush’s letter to the BoCC, “Research conducted in the San Juan Mountains concluded that cloud seeding may increase snowpack levels by an additional 5 to 15 percent. The extra water realized through cloud seeding was produced at a cost of $0.94 to $1.15 per acre foot. Silver iodide is used to seed the clouds.”[…]

    According to a map that accompanies the request letter, the WEA has 12 cloud seeding generators on Grand Mesa.

    More cloud-seeding coverage here.

    Colorado River Basin: What are the reasonable water management options and strategies that will provide water for people, but also maintain a healthy river system?

    coloradoriverbasin.jpg

    Here’s a guest commentary written by Eric Kuhn, David Modeer and Fred Krupp running in The Denver Post. The trio are issuing a call to arms of sort, asking for input for the Colorado River Basin Study. Here’s an excerpt:

    Management of the Colorado River is a complex balancing act between the diverse interests of United States and Mexico, tribes, the seven basin states, individual water users, stakeholders, and communities. The challenges posed by new growth and climate change may dwarf anything we faced in the past. Instead of staring into the abyss, the water users, agencies, and stakeholder groups that make managing the Colorado River responsibly their business are working together, using the best science available to define the problem, and looking for solutions.

    We’re calling our inquiry the Colorado River Basin Study, and we want your help. As Colorado River management professionals, we have a lot of knowledge and ideas, but we know that we don’t have them all. We want ideas from the public, from you, but we need your input by February 1. You can submit your suggestions by completing the online form at: http://on.doi.gov/uvhkUi.

    The big question we need to answer is: What are the reasonable water management options and strategies that will provide water for people, but also maintain a healthy river system? We don’t believe there’s a single silver bullet that will resolve all of our challenges. We want to continue to explore the benefits and costs of every possibility, from conservation to desalination to importing water from other regions.

    The West was built on innovation and hard work, and that spirit is still strong. Our landscapes and communities are unparalleled in their beauty, resilience, and character. The economic well-being of our rural and urban communities in the Colorado River basin is inextricably linked to Colorado River and its environmental health.

    That’s why we are asking for the public’s input to help us craft a study showing a path forward that supplies our communities with the water they need to thrive and protects the health of the Colorado River-and the ecosystems and economies it supports.

    More Colorado River basin coverage here.

    Cloud-seeding: Gunnison County, Mt. Crested Butte, CWCB and the Upper Gunnison River Water Conservancy District ink a deal with North American Weather Consultants for the 2011-2012 season

    cloudseedingexplained.jpg

    From The Crested Butte News (Alissa Johnson):

    In spite of early concerns that funding for cloud seeding might dry up, Gunnison County entered into an operational agreement with North American Weather Consultants for the 2011-2012 winter season on November 15. With the total bill projected at $95,000, a 3.26 percent increase over last year, the Upper Gunnison River Water Conservancy District came through with a $26,500 contribution. The county will contribute $10,000 and Mt. Crested Butte budgeted $3,000. The Colorado Water Conservation Board will cover $47,500 in matching funds, and the remaining moneys will be collected from a variety of local contributors.

    More cloud-seeding coverage here and here.

    Western Weather Consultants report that their cloud-seeding efforts increased Summit County snowfall by 12 to 22 inches last winter

    cloudseedingexplained.jpg

    From the Summit County Citizens Voice (Bob Berwyn):

    This year, the $274,000 central Colorado mountains program includes seven Front Range water providers and four ski areas: Arapahoe Basin, Keystone, Winter Park and Breckenridge, all contributing to the cost of the cloud-seeding program, according Joe Busto, head of the state’s weather modification program. The CWCB supports the program with grant funding…

    The report estimates that last winter’s cloud-seeding between early November and early February resulted in an additional 12 inches of snow at Breckenridge, 16 inches at Keystone and 22 inches at Arapahoe Basin…

    To avoid unwanted consequences such as excessive flooding, cloud-seeding operations stop when certain snowpack thresholds are reached, or if avalanche hazards rise to a critical level. For example, seeding operations in Summit County were suspended last winter during a pre-Christmas storm because of the high snowpack in the area.

    Here’s the link to the report. More cloud-seeding coverage here and here.

    The Lower Arkansas Water Conservancy District heard a pitch for a potential cloud-seeding program at their last meeting

    cloudseedingexplained.jpg

    From The Pueblo Chieftain (Chris Woodka):

    Cloud-seeding, using silver iodide crystals fired from ground cannons, is already widely used in Colorado. Mainly using for increased snowpack in the mountains, the cannons are also used for hail suppression in some areas like the San Luis Valley. There are 111 generators in the state, said Joe Busto, who coordinates cloud-seeding for the Colorado Water Conservation Board. Programs have continued for decades and in the last six years, the state and cooperating agencies have spent $3.9 million for cloud-seeding programs…

    Just over the state line, Kansas has been conducted summer cloud seeding to suppress hail and increase rainfall since 1975, said Walt Geiger, meteorologist for the Kansas program. He explained the Kansas program to the Lower Arkansas Valley Water Conservancy District last week, and suggested a similar approach could help Eastern Colorado…

    Airplanes fly both into and below thunderstorms, using dry ice (frozen carbon dioxide) and silver iodide both to reduce the size of hail and increase rainfall. Updrafts allow silver iodide crystals to flow into the clouds from below. Dry ice is released into the clouds by planes flying near the edges of storms…

    The theory behind cloud-seeding is that it increases precipitation by injecting trillions of nuclei into clouds. That encourages more rain or snow, and reduces the size of hail by creating more targets for loose droplets to cling to in the clouds. Large hailstones gain size as droplets attach to them as they move through clouds. Airplanes are are used on the plains because ground cannons are not effective in reaching the zone where hail forms — about 11,000-16,000 feet above ground, where there are freezing temperatures, even in summer. Above that zone, ice crystals don’t precipitate as easily.

    More cloud-seeding coverage here and here.

    Cloudseeding update

    A picture named cloudseedingexplained.jpg

    From KJCT.com (Dann Cianca):

    George Stowell lives in Gunnison and is the operator of one of the many cloud seeding generators in the county. The generator is actually located in his back yard and works by injecting the cloud seeding solution into a propane burner. The heat carries the particulate that results into the upper levels of the atmosphere where the particles act, in simple terms, as an attractive place for tiny water vapor droplets to gather. Could seeding works by increasing the efficiency by which rain drops or ice crystals form within the cloud. Atmospheric conditions have to be just right for this to work, however, so the generator is typically only turned on a few times per season. The state issues permits through the Colorado Water Conservation Board and these permits only allow the operators to seed at when the permit area will be affected. This basically happens when the wind is blowing a certain way.

    The Gunnison County program has been ongoing for about ten years and is partially sponsored by the county itself. The county isn’t actually the largest source of funding for the program however as many other interests which include agriculture groups, municipal water districts and even ski resorts contribute…

    Operators of these programs say that the science is sound and that it provides good results. With Colorado’s dependency on water, they say that having extra snow-pack can make a huge difference on the economy of the state. That is why these programs have expanded over the years to include many areas of Western Colorado. Generators exist in the San Juans, the Upper Gunnison River Basin, the Grand Mesa area and even near Vail to name a few.

    More cloud seeding coverage here and here.

    2011 Colorado legislation: The Senate Agriculture and Natural Resources Committee votes 4-3 to continue weather modification licenses

    A picture named cloudseedingexplained.jpg

    From The Durango Herald (Joe Hanel):

    On Thursday, state senators recommended the government continue to offer weather-modification licenses for at least another nine years…

    The Senate Agriculture and Natural Resources Committee voted 4-3 to go forward with a bill that continues the licensing program. Without action by the Legislature this year, the state would stop offering licenses…

    Only eight entities do cloud-seeding in Colorado, and three are in Southwest Colorado. The city of Durango and water districts around Bayfield and Pagosa Springs run one program, the Animas-La Plata and Dolores water districts cooperate with Durango Mountain Resort on another, and a third centers on Telluride ski area.

    More cloud-seeding coverage here and here.

    New study questions the effectiveness of cloud seeding

    A picture named cloudseedingexplained.jpg

    From Science Daily:

    …research now reveals that the common practice of cloud seeding with materials such as silver iodide and frozen carbon dioxide may not be as effective as it had been hoped. In the most comprehensive reassessment of the effects of cloud seeding over the past fifty years, new findings from Prof. Pinhas Alpert, Prof. Zev Levin and Dr. Noam Halfon of Tel Aviv University’s Department of Geophysics and Planetary Sciences have dispelled the notion that seeding is an effective mechanism for precipitation enhancement.

    The findings were recently reported in Atmospheric Research…

    During the course of his study, Prof. Alpert and his colleagues looked over fifty years’ worth of data on cloud seeding, with an emphasis on the effects of seeding on rainfall amounts in a target area over the Sea of Galilee in the north of Israel. The research team used a comprehensive rainfall database and compared statistics from periods of seeding and non-seeding, as well as the amounts of precipitation in adjacent non-seeded areas. “By comparing rainfall statistics with periods of seeding, we were able to show that increments of rainfall happened by chance,” says Prof. Alpert. “For the first time, we were able to explain the increases in rainfall through changing weather patterns” instead of the use of cloud seeding.

    More cloud seeding coverage here and here.

    Cloud-seeding update

    A picture named cloudseedingexplained.jpg

    From The Durango Telegraph (Allen Best):

    A half-century after cloud-seeding began in the West, it continues to be regarded by many as something akin to chicken-noodle soup for colds. Or, on the more sinister side, snake oil. But water authorities in thirsty states of the American Southwest have no such doubts. For several winters, they have been increasing their budgets for seeding clouds passing over the mountains of Colorado, where about half of the total volume in the Colorado River originates. “We’re believers down here,” says Tom Ryan, resource specialist with the Metropolitan Water District of Southwestern California. “The lower-basin folks believe it works. We believe that the science is adequate to move forward.”

    While still relatively small, just $152,000 this winter, the money from lower-basin states has more than tripled since 2006. The money has been used to spew silver iodide particles into clouds over the San Juan Mountains, the Gunnison Basin, and Grand Mesa, all regions with ski areas. The states also contributed to renewed seeding operations at Winter Park in partnership with ski-area operator Intrawest. Vail Resorts also continued its seeding operation for Vail and Beaver Creek, a program that began in 1978. It’s Colorado’s longest-continuous seeding operation.

    More cloud-seeding coverage here and here.

    Cloud seeding update

    A picture named cloudseedingexplained.jpg

    Here’s a look at cloud seeding efforts worldwide from the Associated Press via The New York Times. From the article:

    Faced with water shortages, growing populations and the threat that climate change could make matters worse, governments around the globe have increasingly turned to cloud seeding in an attempt to wring more rain and snow from the sky. But the efforts are threatened by budget cuts in states struggling to begin an economic recovery and by critics who insist the technique is unproven and might pose a threat to the environment. ”When there is a drought in a particular country, they start looking at alternative sources of freshwater, and cloudy air is one source,” said Duncan Axisa, a scientist at the National Center for Atmospheric Research in Boulder, Colo., who supports expanding cloud-seeding research.

    Government agencies and utilities from California to North Dakota spend an estimated $15 million a year on cloud seeding, and the number of projects has jumped by nearly a third in the last decade. But spending in the United States is far lower than in many other countries. China spends an estimated $100 million a year on cloud-seeding efforts that include using anti-aircraft guns and rocket launchers to blast the sky with silver iodide. ”What’s going on in the U.S. is tiny,” said Arlen Huggins, an associate research scientist at the Desert Research Institute in Reno, Nev. ”There’s more being done outside the U.S. than here.” Other countries conducting cloud-seeding research include Australia, France, Greece, Saudi Arabia, Turkey and Venezuela.

    In the U.S., utilities that run hydroelectric dams are among the most active cloud seeders. They say it is a cost-effective way to increase limited water supplies by 10 percent or more. Cloud seeding is also used in Texas and the Midwest to make hail smaller, reducing crop damage…

    Colorado has doubled its state and local spending on cloud seeding over the last 10 years to about $700,000 a year. In 2005, Wyoming lawmakers committed nearly $9 million to a five-year project to determine whether the technology works. Cloud-seeding supporters say federal research funding would not only validate the system but lead to improvements in techniques. ”We want to chip away at changes in climate change now and do a good job at augmenting our precipitation now,” said Joe Busto, who sits on the North American Interstate Weather Modification Council, a group of regulators from 10 states organized to promote cloud seeding.

    More cloud seeding coverage here and here.

    Denver Water and Winter Park Resort to pony up $110,000 for cloud-seeding

    A picture named cloudseedingexplained.jpg

    From the Sky-Hi Daily News (Tonya Bina):

    [Winter Park] and Denver Water are sharing the $110,000 cost of the project, which will take place in locations within 35 miles of the ski area. Denver Water last partook in cloud seeding over Winter Park in 2002-2003 and 2003-2004. The project is slated to take place during the months of November, December and January, according to Steve Schmitzer, manager of water resource analysis for Denver Water.

    Meanwhile, a supporting $60,000 cloud-seeding project will take place from November through March in the same area coordinated by the Colorado Water Conservation Board and water users from the lower Colorado River basin states of Arizona, California and Nevada…

    About 10 Winter Park-Denver Water financed generators will be located on mostly private properties, and will be turned on and off depending on weather conditions and the presence of moisture-producing clouds. The two other generators will be located in higher areas and managed remotely by computer. The project involves a meteorologist who will determine appropriate times for cloud seeding. The quantities of iodide present in runoff due to cloud seeding equates to less iodine that what is found in salt on food, according to report on cloud seeding during the 2008 Arizona Weather Modification Conference. There is also more silver exposure found in tooth fillings, and there have been no human effects from cloud seeding found in 40 years of research, the report reads.

    More cloud seeding coverage here and here.

    Southwestern Colorado: Local cloud seeding projects

    A picture named cloudseedingexplained.jpg

    Here’s a background piece on cloud seeding in southwestern Colorado from Kristen Plank writing for the Cortez Journal. She has written a nice primer on the subject also. From the article:

    [Larry] Hjermstad, founder of Western Weather Consultants LLC, seeds locally for approximately 10 different entities that support the cloud seeding program, from the town of Telluride to the Dolores Water Conservancy District.

    The DWCD invests in two of Hjermstad’s cloud seeding programs in hopes to increase inflow into McPhee Reservoir. Mike Preston, manager for the DWCD, said the water district has played a part in the program since 2000, and paid approximately $17,000 for the 2008-2009 winter program. “Ski areas are investing in the program for the snow to ski on, but our interest is pure and simple,” Preston said. “If we can increase the inflows into the McPhee Reservoir by some percentage, then everyone benefits.”[…]

    Hjermstad recounted an independent study done by Bernard Silverman, prior chief scientist with the U.S. Bureau of Reclamation, that showed the effects of a 33-year cloud seeding program on Vail’s surrounding streams. The study, lasting from 1977 to 2005, showed an eight to 30 percent increase in stream flows. “(Silverman) wasn’t looking at snow as being of value, but rather water as being of value,” Hjermstad said. “The study verified that precipitation increases are reflected in stream flow increases. To me, this is the missing ‘ground link’ for what we are trying to do with precipitation.”[…]

    Cloud seeding, or weather modification practices, is a popular process throughout the world. Locally, a total of 34 “ice nuclei” generators are spread across the San Juan Mountains, working from November through the end of March. Hjermstad will have operators turn on generators for roughly 24 storms during a three-month period.

    Well over a trillion seemingly invisible silver iodide nuclei will work their way into the bottom portion of a cloud system, where they will attract moisture, produce snowflakes and fall to earth. The compound works so well at producing additional snowfall because of its nearly identical characteristics to an ice crystal. It’s as safe as one, too, Hjermstad said. “One reason silver iodide was chosen was because, as a molecule, it is extremely tightly held together once the two elements combine,” he said. “Nothing in nature breaks it apart.” This includes the sun, the photosynthetic process in plants, or anything from the digestive systems of humans, animals or aquatic wildlife. Hjermstad said that cloud seeding programs also do not take away from any precipitation that may have been dispersed into towns downwind.

    More Coyote Gulch coverage here and here.

    Four years of Wyoming cloud-seeding efforts

    A picture named cloudseedingexplained.jpg

    Here’s an update on Wyoming’s 5 year cloud-seeding project, from Wes Smalling writing for the Casper Star Tribune. From the article:

    [Bruce] Boe is one of several scientists working on the five-year Wyoming Weather Modification Pilot Project, an $8.8 million research program funded by the state of Wyoming. The project’s scientists, along with state water managers, hope to find proof of whether the decades-old practice of seeding clouds — trying to squeeze more precipitation out of passing storms — actually works and that it’s a practical option for increasing the state’s water supply. Members of the world’s science community — cloud-seeing advocates and skeptics alike — are watching the project closely. “For a scientist doing research, this is it. As far as in terms of the research, it is the biggest in the United States by far,” Boe said…

    The Wyoming project is in its fourth year, only the second winter in which cloud seeding in earnest has actually been performed. The first two years involved mostly taking measurements and weather readings, obtaining permits from the U.S. Forest Service, gathering other statistical data and getting equipment in place…

    While Boe’s company is contracted to perform the cloud-seeding operations, independent teams of scientists from the Colorado-based National Center for Atmospheric Research and the Desert Research Institute in Nevada are independently evaluating whether any increases in precipitation that occur are from cloud seeding or from just normal variations in the weather. That’s the real trick to proving if it works. Cloud-seeding scientists estimate that, if done properly, pumping silver iodide into a cloud will increase snowfall in most cases by about 10 to 15 percent. That’s roughly the same percentage of natural variability possible in normal weather patterns…

    It’s too early to say with any certainty that Wyoming’s cloud seeding is working to make more snow, but the scientists are beginning to amass a massive amount of vital information from the project. They still have much more data to collect. They conducted 26 four-hour seeding events in southern Wyoming last winter and more than 30 this winter. Ideally, they would like to have more than 200 cases to examine by the end of the five-year project…

    While clouds are often seeded from airplanes, the seeding on the Wyoming project this winter is all being done from the ground by generators on 20-foot towers. Inside a generator placed upwind, a propane flame heats the silver iodide solution, and a nozzle sprays it into the air. It rises into the cloud and is carried by the wind to a target area, which is where the scientists want it to snow. There are eight generators in each mountain range, the Snowies and the Medicine Bows, and another seeding site on the west side of the Wind River Range that has 10 generators.

    Meteorologists determine when conditions are right for seeding and tell the technicians which generators to turn on. The technicians, sitting many miles away at computers, activate the generators remotely through satellite modems. Boe, using a machine in his cabin called an acoustic ice nucleus counter, checks the outside air during seeding operations to detect the presence of silver iodide to make sure the particles are reaching the target area…

    Before, during and after seeding events, the weather is monitored closely. Independent evaluation teams from NCAR and DRI check the snow for the presence of silver iodide and to collect other statistical data. Seed generators are never turned on at the same time in both the Snowy Range and Medicine Bow Mountains — only randomly either in one mountain range or the other. The forecasters and evaluators are not told which mountain range was seeded, which should eliminate any bias in their predictions and conclusions, said Dan Breed, lead scientist for NCAR. Seeding only one range at a time also allows researchers to collect a double dose of data from each storm — one from a seeded mountain range and one that only received natural snowfall. Comparing results between the two ranges could help determine if increases in snow were a result of seeding or that ever-elusive variability that occurs with natural snowfall…

    Periodically this winter, [University of Wyoming] professor Bart Geerts and graduate students will fly over snowstorms in a Kingair research aircraft as cloud-seeding experiments are going on to study how the clouds are affected. Using technologies called cloud radar and LINAR, short for Light Detection and Ranging, the crew will take snapshots of the clouds similar to the three-dimensional slices of a medical MRI scan. “We are basically trying to look at it in the finest detail in time and space. We’re actually looking at the cloud as it is injected with silver iodide,” Geerts said. When a cloud is seeded, “The idea is that silver iodide injected into a cloud is going to turn all that liquid water into ice pretty quickly. We want to see if that really happens.”[…]

    University of Tennessee professor Glen Tootle is leading a study on the effects of an increased snowpack on spring and summer runoff. The university experiment could determine what a small snowpack increase in the Medicine Bow Mountains would mean for the North Platte River drainage. No one knows for sure if 10 percent more snow created from cloud seeding would necessarily produce 10 percent more water for the state’s supply. “Those basic questions have not been answered,” Geerts said.

    More Coyote Gulch coverage here.