Cooperative Extension Service Communications and Technology Department 3354 1000 E. University Ave. Laramie, WY 82071 (307) 766-6342 • fax (307) 766-3998 • www.uwyo.edu

 

For Immediate Release

 

 

Contact: Steven L. Miller, Senior Editor

Phone: (307) 766-6342

E-mail: slmiller@uwyo.edu

Archived News Site www.uwyo.edu/agadmin/news/news.htm

 

Date: Feb. 26, 2006

State climatologist: Wyoming precipitation either feast or famine

            It’s no news parched Wyoming is enduring a multi-year drought. But what about this spring and early summer?

            Flip a coin.  Expect slightly warmer temperatures and a 50-50 chance of either higher than normal or lower than normal moisture, related Steve Gray, Wyoming state climatologist (www.wrds.uwyo.edu/wrds/wsc/wsc.html).

            Gray, speaking to members of the Wyoming Agricultural Experiment Station at the University of Wyoming in Laramie Feb. 21, emphasized his office isn’t in the business of putting out forecasts – he compiles and puts into a Wyoming perspective forecasts from many agencies like the National Weather Service and Climate Prediction Center.

            The warmer temperatures and coin flip prediction for precipitation holds through May, he added.

            Wyoming ended 2005 and entered 2006 with average winter moisture and snow pack, but two events wiped out most of these moisture gains: the snowmelt began up to one and one-half months earlier, and typical late spring and early summer precipitation never happened.

            “Early snowmelt and a lack of April through June precipitation are critical pieces of the puzzle for understanding how the drought evolved last year,” he said.

            That led to dreary drought maps that have aimed a bull’s-eye at Fremont County, with some areas having received only 10 percent of the late spring and early summer average last year.

            Above-average temperatures baked the state, and many areas received less than 20 percent of their average precipitation last summer. “That one-two punch put us in a bad situation by the end of summer,” Gray said.  “Now we are left with a very large, long-term deficit. It’s going to take a long time to get out of it.”

            Many areas of the state saw 50 to 60 percent of normal precipitation over the last 12 months and, over a two-year period, parts of Fremont, Carbon and Sweetwater counties received about 30 percent of average.

            Tree ring comparisons and water flows the past 500 years at Lees Ferry on the Colorado River show the current drought is severe but not among the worst. “While the current drought is bad, it’s not unprecedented,” noted Gray. “It’s in the range of the top 10 shorter-term droughts but not outside of what we should expect.”

            Over the last 500 years, the tree-ring record also shows periods of extreme long-term drought. “For extended periods, it became dry and stayed dry for several decades,” he said.

            Similar records for the North Platte River show the current drought is severe, perhaps in the top five.

            Wyoming averages about 17 inches of precipitation, fifth-driest in the nation behind Nevada (10 inches), Arizona, Utah and New Mexico. The national average is 37 inches.

            “The climate in Wyoming doesn’t spend much time at average,” said Gray. “Precipitation is either way up or way down, either feast or famine.”

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