Wyoming Drought Information and Graphics--updated January 22, 2008

…Upper Yellowstone Basin and northern portions of the Snake River Watershed see improved drought conditions…

 …Wyoming snowpack averages still below average--at 87 percent of average…

 …January water supply forecast numbers indicate generally below average snowmelt streamflow volumes for 2008… 

 …All major basins across Wyoming had near normal to well above normal precipitation totals for December…

The Upper Yellowstone River Basin and a large portion of the Snake River Watershed had improved drought conditions during December and early January.   Both areas were upgraded from having moderate to severe hydrologic drought conditions to having abnormally dry to moderate hydrologic drought conditions.  

There was a steady increase in snow water equivalents (SWEs) in the Wyoming snowpack during December and into the middle of January.  The state-wide average SWE at the end of December was 87 percent of average.  The Little Snake River Basin had the highest average SWE at 108%: while the Upper Green had only 73 percent of average SWE.  Average to below average temperatures coupled with generally well above normal precipitation during December greatly aided in the steady increase in SWEs at many of the major drainages across Wyoming.

The January water supply forecast indicates that most of the state will see below average streamflow volumes during the spring and summer of 2008.  The Upper Yellowstone, Snake, Shoshone, Clarks Fork, Little Snake, and Laramie Watersheds are expected to see normal to above normal snowmelt stream volumes this spring and summer.

Precipitation averages across the state for December were above to well above normal. Rainfall totals across the major watersheds across the state varied from 83 percent of average over the Shoshone/Clarks Fork Basin to 302 percent of average over the Crow Creek/Niobrara Basin. Many other major basins across the state received well over 150 percent of normal precipitation for the entire month.

Yearly rainfall totals for 2007 across Wyoming varied from 113 percent of average at Casper to only 77 percent of normal at Lander.

The latest drought outlook through April 2008 indicates that most of central and western Wyoming will continue to see improvement in current drought conditions; while eastern and southeastern Wyoming will see little improvement to current drought conditions.

 

 

 For the rest of the Wyoming Drought Information Statement and Graphics (in .PDF format)---please go to:

 

  http://www.crh.noaa.gov/images/riw/hydro/drought_info.pdf



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