April sees above average precipitation numbers

by Mark Dykes

April precipitation totals across Wyoming were 150 to 160 percent of average. Precipitation numbers varied between near 250 percent of normal over the Tongue River Drainage in north central Wyoming to near 110 percent of normal over the Lower Green Basin in southwestern Wyoming. The current water year, October 2016 to April 2017, precipitation across Wyoming is averaging 140 to 150 percent of average.

Mountain snowpack across Wyoming was 125 to 135 percent of median by early May. Snowpack “water” numbers and/or SWEs were the highest across basins in central Wyoming (Wind, Upper Green, and Sweetwater)—varying between 190 to near 230 percent of median. SWEs across basins in southeastern Wyoming were 85 to near 100 percent of median.

Above, to much above, normal — 160 to near 175 percent — snowmelt streamflow volumes continue to be expected across almost all major basins across Wyoming. Well above average — 180 to 250 percent — snowmelt streamflow volumes are still expected across the Snake, Wind, Sweetwater, Shoshone, and Upper Green Watersheds. The Little Snake, Upper North Platte, and Laramie Basins are forecasted to have slightly below to slightly above normal streamflow volumes during the upcoming snowmelt season.

Reservoir storages across Wyoming remained above average at 125 to 135 percent for May.