Exploring the Colorado River and Lake Powell – News on TAP

Scenic views dominate the Colorado River, Lake Powell and Lake Mead in the southwest, areas that are critical to Denver’s water supply.

Source: Exploring the Colorado River and Lake Powell – News on TAP

#LaNiña brings below normal precipitation and above normal temperatures — The Fence Post

From The Fence Post (Amy Hadachek):

After fall harvest winds down, the big question for farmers and ranchers is what will La Nina bring for this winter in the Rockies and central Plains states?

“La Nina is here, and not going anywhere. Still looking very dry on the Plains this winter,” said Kyle Mozley, meteorologist at the National Weather Service in Pueblo, Colo.

The Climate Prediction Center’s early Winter Outlook issued Thursday, Oct. 15, 2020, is forecasting cooler and wetter weather in the northern states, and largely warmer and drier weather in the southern states. However, being smack in the middle from Colorado to Wyoming, and into the central Plains the National Oceanic and Atmopheric Administration favors near to slightly below normal precipitation, and near to slightly above normal temperatures across the central Plains.

Looking at past moderate events, the upper pattern features ridging over the western U.S. and troughing over the east, with northwesterly flow across Colorado.

COLORADO

“Areas of the Pacific Northwest and Ohio Valley will likely do well this winter, while leaving Colorado and Kansas warm, dry and windy, typical for La Nina in the Rockies into the central Plains,” said Mozley, adding, “This matches up with the CPC forecast with warm and dry conditions across Colorado into Kansas, not good for our already drought stricken-rangelands.”

It has been exceptionally dry for the past six months across eastern Colorado and western Kansas…

While the climate pattern Pacific Decadal Oscillation (PDO) will continue in a negative phase through the winter, likely enhancing warm and dry across Colorado, another climate driver the Madden Julian Oscillation forecast (an eastward moving disturbance that traverses the planet) has potential for a brief stormy pattern in late November to early December (around Nov. 24-Dec. 10). While the overall outlook is for dry, drought conditions into spring, the Arctic Oscillation (AO) could also bring surges of colder air to the Plains, Mozley said.

WYOMING

With temperatures already in the low 20’s and some snow already seen in parts of Wyoming, summer has been doing somersaults over autumn.

With drought reported to be occupying 45 percent of the U.S., largely over the western half of the country (but also in the northeast) many are anxiously hoping for moisture. However, currently most of Wyoming (almost 90 percent) is in one level of drought or another with the northwest part of the state being the only area in either pre-drought (D0) or no drought.

“Over 97 percent of Wyoming is impacted. Teton is the only county that has no drought or pre-drought in it. Given the precipitation expectations and with above normal temperatures expected for at least the next several weeks statewide (and for the upcoming months in the southwest) drought conditions, especially in the southern half of the state should be expected to continue and intensify,” said Tony Bergantino, interim director of the Water Resources Data System at the Wyoming State Climate Office and Wyoming Community Collaborative Rain, Hail, and Snow state coordinator.

In the short-term, after some brief cold and wet conditions continuing through October, Wyoming will be again looking at higher chances for above normal temperatures for November and for the November to January period…

Thankfully, for November through January, there are actually greater chances of above-normal precipitation for the northern half of Wyoming, which brings hope. The chances in the southern half are equally distributed between above normal, below normal, or normal.

NEBRASKA

A Nebraska meteorologist sees some positive signs for moisture, even during a La Nina winter. Instead of just cold and drier, that means Nebraska and the central Plains could expect a lot of ups and downs temperature-wise and the windy conditions those weather systems will bring. Then also, despite the relative confidence in the impacts of La Nina on the upcoming winter, the weather across Nebraska and Kansas may end up a bit of a mixed bag, especially in terms of temperature.

“Also, during La Nina influenced winters, temperatures often vary widely from above to below normal thanks to frequent weather systems rolling across the central Plains from the northwest. Long range precipitation outlooks are notoriously difficult, but the impacts of La Nina can be somewhat helpful in looking ahead. Typically, during La Nina winters, precipitation on the central Plains is no more than normal, and often below normal. La Nina also impacts precipitation timing, with wetter conditions in December and January, and the drier months during the second half of the winter (February and March),” said Michael Moritz, warning coordination meteorologist for the NWS in Hastings, Neb.

Should warmer than normal temperatures and near or below normal precipitation occur, the winter ahead is likely to result in expanding drought conditions across the central and southern Plains, including Nebraska and Kansas. “NOAA expects drought conditions to worsen in areas already hit hard by drought, and for drought conditions to expand from Nebraska to Texas by mid-winter. With depleted soil moisture already, the impacts of drought could spill into next spring,” said Moritz.

It will really boil down to whether the La Nina dissipates next spring or is able to maintain itself for a second consecutive year. Right now, all of the models end La Nina by late spring…

KANSAS

Kansas Climatologist Mary Knapp points out that precipitation in November is critical to maintain and establish fall planted crops, including winter wheat, canola and cover crops.

“Even wetter than normal conditions are unlikely to improve the current drought conditions,” said Knapp, assistant state climatologist at Kansas State University in Manhattan.

Kansas is expected to be on the dry side this winter, but that doesn’t necessarily mean quiet. “Strong (cold) fronts are still likely, bringing high winds without much moisture. This increases the likelihood of dust storms (such as last weekend), and high fire danger,” Knapp said.

Knapp’s other take-aways from the CPC Winter Outlook:

• It is dry and getting drier.

• Warm temperatures, low humidities and windy conditions are increasing evaporative demand, drawing down stock ponds at a faster rate than usual at this time of the year.

• Given the normally dry nature of winter even above normal precipitation may not reduce the drought.

— Hadachek is a freelance writer who lives on a farm with her husband in north central Kansas and is also a meteorologist and storm chaser. She can be reached at rotatingstorm2004@yahoo.com

Northern Front Range water supply safe in spite of fires — for now — The #Greeley Tribune

Colorado Rivers. Credit: Geology.com

From The Greeley Tribune (Cuyler Meade):

…while a significant portion of the water supply that is held and accessed by the project that serves the northern Front Range communities is impacted by the fires, the water supply itself is not in danger.

According to Jeff Stahla, public information officer for the Northern Colorado Water Conservancy District — or simply Northern Water — the near-term supply is fine.

The decision to close off a tunnel — which transports water pumped from Lake Granby to Shadow Mountain Reservoir before traveling by gravity through the tunnel through Rocky Mountain National Park to Lake Estes and elsewhere, before eventually settling in Horsetooth Reservoir and Carter Lake in Fort Collins and Loveland — will not impact the water supply that’s eventually drawn from those two reservoirs to supply much of Northern Water’s million-plus customers in Northern Colorado, including Greeley.

That’s because, Stahla explained, the system is proactive. While new water will not be replenished quite according to the normal schedule in the Horsetooth and Carter Lake reservoirs, that water is, in essence, paying down a future withdrawal that won’t happen for a year or more…

“The water coming out of your faucet now, if it’s this project’s water, was probably snow that fell in maybe 2018,” Stahla explained. “It ran off in spring of ’18 and filled up Lake Granby, and then around the end of 2018 into 2019, it would’ve been used to fill up reservoirs on the front range. That would’ve happened over winter of 2018-2019, and then it would’ve been in reservoirs all of 2019 and probably drawn out now in 2020. This project works on a multi-year cycle of gathering runoff, feeding reservoirs and serving the public.”

The water is still in Lake Granby, but temporarily won’t be pumped up to Shadow Mountain because of concerns that the fire will impact the power supply to the pump at Lake Granby…

However, that water is only a portion — a very sizable portion, close to half — of the water that is used by Greeley customers, according to city of Greeley water and sewer director Sean Chambers.

And, truly incredibly, the other major sources of water, four in total, from which the city draws its 20,000 to 25,000 acre feet-per-year supply are also being impacted by these unfathomable wildfires.

“We have water from four different river basins,” Chambers said. “We get water from the Poudre River Basin, that’s where the year-round treatment plan by Bellevue, northwest of For Collins is. The top of the Poudre is where the fire started. You go north and cross into Laramie River Basin — the Laramie flows north into Wyoming but we have a system of ditches and tunnels that brings water back into the Poudre. The fires burned a bit of the headwaters of the Laramie. We also get water from the Big Thompson Basin, and the Cameron Peak Fire spread southeast over the last ten days, blown over the ridge line and the divide into the Big Thompson Basin. And then the last basin is the Colorado River Basin, which is where the East Troublesome Fire comes from.”

Chambers, marveling, called this phenomenon the first time “in recorded history” that this has happened, where all four major water sources are affected by fires at the same time…

Further, while snow melt over burned land could well impact other water sources as well, there are plans in place, Chambers said.

“When the High Park Fire happened, that fire had these post-precipitation water-quality events in the river, where Fort Collins and Greeley and others, who take water directly off the Poudre River for municipal treatment, we turned off our intakes and let the bad water go by, let the water quality improve. We can do that because of the beautiful supplemental supply in the Colorado Big Thompson project.”

The flexibility requires planning, though, including, Chambers said, installing source-site filtration systems where snow runoff on its way the river systems are filtered prior to entering the water supply…

In the immediate moment, though, the water supply even well into next year is in good shape, regardless of the fires Stahla said.

“Not even just into early next year,” Stahla said. “Reservoirs are there for that kind of demand management that you can have some stocked away close to meet your needs. As of now, there’s no operational changes because of the wildfires to the water supply on the Northern Front Range. Those reservoirs will be refilled by next spring.”

As #Colorado wildfires burn, fears that #ClimateChange is causing “multi-level emergency” mount — The #Denver Post

From The Denver Post (Bruce Finley):

The record-breaking forest fires burning in Colorado even as winter sets in are the latest sign climate warming is hitting the West hard, causing scientists to up their rhetoric and warn it is past time to move beyond planning and start aggressively acting.

“We’ve got to get motivated and stop turning the thermostat up. That is urgent, not a sci-fi thing. It is us turning up the thermostat. It does not readily turn down. The farther we turn it up, the worse it will get,” said Scott Denning, a Colorado State University atmospheric scientist…

The rising heat is depleting water and drying soil across the Colorado River Basin and other river basins. Last week, federal authorities classified 97% of Colorado in severe to exceptional drought.

Mega-fires including 2020’s Cameron Peak, East Troublesome and Pine Gulch are burning hotter and longer, with record destruction this year of 700,000 acres in Colorado and 6 million around the West. The smoke that exposed tens of millions of people to heavy particulates, health researchers say, will pose an even greater risk to public health in years to come…

Yet efforts to help residents cope, and even draw down heat-trapping carbon dioxide in the atmosphere by re-greening farmland and cities, have barely begun. A Denver Post examination found a $4.2 billion backlog of forestry work identified by the Colorado State Forest Service as critical to protect people and property from fires…

Farmers are left largely on their own as water vanishes and crops wilt. Local governments still approve urban expansion despite water supply strains…

Colorado’s average temperature has increased since 1990 by 2 degrees, faster than the global increase, with temperatures in western Colorado increasing more, said Clay Clarke, leader of a four-member climate team in the Colorado Department of Public Health and the Environment.

“And we will see years hotter than what we’ve had,” state climatologist Russ Schumacher said. “There’s very high confidence in the climate science community that this warming is going to continue… and because the atmosphere is thirstier in hot years, what moisture you have goes away more quickly.”

[…]

Across the Southwest, the rising temperatures are drawing down water supplies, especially in the Colorado River Basin, where the crucial Lake Mead reservoir has dropped to 39% full and precious precipitation vanishes before it reaches rivers.

Streams and rivers in the basin will lose about 4% to 5% of water for every 1 degree temperatures rise, said Jeff Lukas, author of the 2020 Colorado River Basin State of the Science report done for Denver Water, the Colorado Water Conservation Board and other water agencies. By the end of the century, stream flow will decrease by 12% to 15% due to warming, he said.

A need to adapt became clear over the past 15 years as warming depleted water in the Colorado River by at least 6%, said Brad Udall, a CSU water center scientist who analyzes federal flow data.

What’s the rational response?

“Rationality means getting really serious about GHG (greenhouse gas) reductions. It also means planning for the worst with respect to water supplies and fires. We’re doing none of these things, although the water community at least realizes the threat and is making some efforts to think about it,” Udall said.

“Climate change is the ultimate ‘kick-the-can-down-the-road’ game. To fix it you have to have pain now, and reap the benefits later. That’s never a good setup for political action.”

[…]

The bigger burning, in turn, worsens respiratory health as people inhale tiny particulates that lodge in their lungs and clog airways, straining heart and lung functioning.

Multiple weeks and even months of exposure to fire smoke in cities will lead to “increased respiratory infections and mortality,” said Emily Fischer, a researcher for CSU’s program on air, climate and health, who had just measured an Air Quality Index reading of 368 — hazardous — in Fort Collins…

Colorado has nearly completed a statewide inventory that estimates emissions from multiple sources of CO2, methane and other heat-trapping gases that drive climate warming. It will lay the groundwork for enforcing tougher regulations.

Lawmakers have ordered cuts below 2005 levels — 30% by 2025, 50% by 2030 and 90% by 2050. Colorado’s emerging strategy would meet those goals by requiring a faster shift away from gas-power to zero-emission vehicles; closing coal-fired power plants; reducing methane pollution by the oil and gas industry; and making the heating and cooling of buildings more efficient.