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.