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Drought a bigger worry than flooding this year, water-watchers predict
Apr 25, 2012 - By Christina George and Martin Reed, Staff Writers
Potential for flooding from springtime snowmelt in Fremont County and across Wyoming is low this year, weather officials say.
The forecast is based on recent above-average temperatures and below-average precipitation, which have combined to deplete mountain snowpack drastically.
Jim Fahey, a Riverton-based hydrologist for the Wyoming National Oceanic and Atmospheric Administration, said there is little concern about problematic runoff in the Wind River Basin.
"We've lost a lot of the 8,500 to 9,700 (feet in elevation) snowpack in March and April because of the temperatures," Fahey said. "Unless temperatures really drop, we're not going to accumulate much snow in those elevations."
The lack of snowpack in the higher elevations is creating a concern for others who rely on the water for critical agricultural functions and other uses.
On the Wind River Indian Reservation, acting tribal water engineer Mitch Cottenoir said the Shoshone and Arapaho Water Resource Control Board issued a drought warning for the area effective April 12 through May 30.
"It's due to the snowpack in the mountains. Right now it's, I believe as of Monday, it was like 58 percent," Cottenoir said. "It's pretty much the whole state is in the same situation."
Statewide, Fahey said the only substantial snowpack to cause significant snowmelt runoff is between 9,000 and 10,000 feet.
"Mountain snowpack water numbers continue to be the highest across the western and eastern slopes of the Big Horn Mountains but are much lower than in late March," he said. "Moderate potential for snowmelt runoff flooding is expected along headwater locations along the eastern Big Horn Watershed."
The above-average temperatures have hastened some seasonal changes, including leafing trees and blooming flowers, by as much as five weeks.
The Wind and Little Wind rivers usually see peak flows in June, but with the warming trend, "we could see it as early as mid-May," Fahey said. "Things have shifted."
Although March and April saw several record-breaking high temperatures and have been drier than normal for the area, Fahey said the next two months could still bring precipitation.
"May has been a historical wet month for us, even during the drought years in the early 2000s," he said. "About 50 to 60 percent of our precipitation comes in May and June."
Fahey said it's too soon to tell if there will be a drought this year.
"The spring rains will probably keep it at bay," he said. "It's too early to say."
Cottenoir agreed that weather could shift and result in a wet summer.
"It will all depend on the weather and spring moisture," he said.
"The drought warning is in effect until May 30, then we will re-evaluate it at that time," he said. "We may go into a drought declaration at that time. It all depends on the spring moisture."
Fahey said there are three ways to predict a drought, with the first being low spring rains. The second involves a meager snowpack, and the third is if there is a low storage of water in the area's reservoirs.
"Our reservoir storage is still pretty good. The Boysen causeway is still high," Fahey said.
Cottenoir has an important warning for water users who work with the Wind River Water Resource Control Board that issued the drought warning.
"Conserve water as much as we can. We're going to be a conservation mode probably throughout the summer. Conserve where possible," he said.
The tribal warning affects the Wind River and Owl Creek basins. A notice from the board warns that "basin residents should keep the prospect of drought in mind while making plans for agricultural, rangeland and recreational water uses."