April 1, 2020 Spring and Summer Streamflow Forecasts
Upper Missouri Basin
The high elevation snow pack in the Upper Missouri Basin as of April 1 was above average. The snow pack above Fort Peck, Montana was 115 percent. The snow pack in the St. Mary Basin was 130 percent, and the Milk River Basin was 183 percent.
March precipitation across the Upper Missouri Basin was near to below average. Basin precipitation summaries for the Missouri Basin include: Milk St. Mary, 87 percent; Milk Canada, 49 percent; Lower Milk, 59 percent; above Toston, 92 percent; Toston to Ft. Peck, 86 percent.
March 2020 Upper Missouri Mean Precip Oct-Mar WY2020 Upper Missouri Mean Precip
Stream flow in the Upper Missouri Basin is forecast to be near average during the upcoming Spring and Summer. The St. Mary River is forecast to have 114 percent of average April-September flows. Runoff is expected to range around 103 percent of average for the Missouri Basin above Fort Peck, Montana.
Upper Missouri March 1, 2020 Spring and Summer Streamflow Forecasts
Of the four major irrigation reservoirs in Montana; Lima Reservoir had 154 percent average storage, Clark Canyon was holding 116 percent of average water, Gibson Reservoir had 51 percent of average stored water, and Fresno Reservoir had 123 percent of average stored water.
The major hydroelectric reservoirs in Montana (Canyon Ferry and Fort Peck), had monthend storage in the average to above average range; 96 and 118 percent of average water, respectively.
Yellowstone Basin
The high elevation snow pack in the Yellowstone Basin was above average on April 1. The snow pack in the Upper Yellowstone Basin was 121 percent of average. The snow packs in the Wind, Bighorn, and Shoshone Basins were 109, 112, and 111 percent of average, respectively. The snow packs in the Tongue
and Powder basins were 103 and 115 percent of average, respectively.
Precipitation during March was mostly below average. The upper Yellowstone River Basin received 109 percent of average precipitation while the Lower Yellowstone River Basin reported 57 percent of average. The Bighorn Basin received 42 percent of average precipitation while the Wind River Basin received 68 percent of average. The Little Bighorn - Upper Tongue Basin received 35 percent of average and the Powder River had 44 percent of average precipitation.
March 2020 Yellowstone Mean Precip Oct-Mar WY2020 Yellowstone Mean Precip
Forecast stream flow in the Yellowstone Basin is near average for the upcoming Spring and Summer. Stream flow for the Yellowstone River above Sidney, Montana is forecast to be about 108 percent of average. Flow in the Tongue Basin is expected to be 115 percent of average. Flows in the Powder River are expected to be about 133 percent of average.
Monthend storage at Boysen Reservoir was 110 percent of average. Stored water in Buffalo Bill Reservoir was 131 percent of average. Monthend storage was 99 percent of average at Bighorn Reservoir.
Yellowstone March 1, 2020 Spring and Summer Streamflow Forecasts
Platte Basin
The high elevation snow pack in the Upper North Platte Basin was 113 percent of average on March 1. The snow pack in the North Platte Basin below Seminoe Reservoir was 115 percent of average. The snow pack in the South Platte Basin was 117 percent of average.
Precipitation during March in the Upper North Platte Basin was 70 percent of average. In the Lower North Platte Basin, precipitation was 76 percent of average. The North Platte Plains below Guernsy Reservoir had 65 percent. The South Platte Mountains had 92 percent whereas the Plains had 145 percent of average March precipitation.
March 2020 Platte Mean Precip Oct-Mar WY2020 Platte Mean Precip
Stream flow in the Platte Basin is forecast to be near to below average during the upcoming Spring and Summer. Runoff for streams above Seminoe Reservoir are expected to be about 108 percent of average. Streams in the South Platte Basin above South Platte, Colorado can expect 93 percent of average flow. For the remainder of the South Platte basin, flows are expected near 93 percent.
Stored water in the South Platte Basin was 110 percent of average on April 1.
North Platte Streamflow Fcst South Platte Streamflow Fcst
