Spring snow is improving the snowpack picture for the Big Horn Basin, although it remains below the 30-year average.
The Bureau of Reclamation released its April through July runoff forecast last week and the Buffalo Bill Reservoir, Shoshone River system is closest to average at 93% of the 30-year average.
The April-July inflow is forecast at 700,000 af. The 30-year average is 749,000 af.
It’s a bit of good news for many Wyoming agricultural producers amongst a tough season, the University of Wyoming Extension said, as a drought is making conditions difficult through much of the region.
National Weather Service models have the cool ocean currents of La Niña affecting the flow of storms across the Northwest, precipitation falling to areas north of much of Wyoming.
February through May are typically the state’s snowiest months.
Mountain basin snowpack totals are edging toward average and in some places are above normal. That doesn’t help rangelands. The U.S. Drought Monitor map for Wyoming in late February showed extreme drought ballooning in central parts of the state, from the Colorado border to just south of Sheridan County, flowing into Carbon, Sweetwater, Natrona, Fremont, Hot Springs, southeastern Big Horn, Converse and Johnson counties.
Runoff in the rest of the Big Horn Basin is further below average.
Bighorn Lake-Bighorn River inflow to Bighorn Lake is forecast to be 74% of the 30-year average.
Boysen Reservoir-Wind River April through July inflow to Boysen Reservoir is forecast at 72% of the 30-year average.
Bull Lake Reservoir April through July snowmelt runoff into Bull Lake Reservoir from Bull Lake Creek is expected to be 83% of the 30-year average.
Wind River April through July snowmelt runoff into the Wind River above Bull Lake Creek is 80% of the 30-year average.
Weather forecasters such as Don Day in his podcasts compare La Niña’s effects to those in 2011-2012, severe drought periods. Recent, new models predict La Niña’s persistent effects through spring and early summer similar to what happened last year – bad news for Wyoming, Nebraska, Colorado, Kansas, New Mexico, Arizona and California, he said.