April 1, 2023 Spring and Summer Streamflow Forecasts
Upper Missouri Basin
The high elevation snow pack in the Upper Missouri Basin as of April 1
was near to above average. The snow pack in the St. Mary Basin was 91 percent,
and the Milk River Basin was 252 percent.
March precipitation across the Upper Missouri Basin ranged from above to below
average. Basin precipitation summaries for the Missouri Basin include: Milk St. Mary,
60 percent; Milk Canada, 100 percent; Lower Milk, 152 percent; above Toston,
154 percent; Toston to Ft. Peck, 119 percent.
March 2023 Upper Missouri Mean Precip Oct-Mar WY2023 Upper Missouri Mean Precip
Stream flow in the Upper Missouri Basin is forecast to be
below average during the upcoming Spring and Summer.
The St. Mary River is forecast to have 53 percent of average
April-September flows. Runoff is expected to range around
93 percent of average for the Missouri Basin above Fort Peck,
Montana.
Upper Missouri April 1, 2023 Spring and Summer Streamflow Forecasts
Of the four major irrigation reservoirs in Montana; Lima
Reservoir had 57 percent average storage, Clark Canyon was
holding 82 percent of average water, Gibson Reservoir had 28
percent of average stored water, and Fresno Reservoir had
58 percent of average stored water.
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 115 percent
of average. The snow packs in the Wind, Bighorn, and Shoshone Basins were 121,
114, and 106 percent of average, respectively. The snow packs in the Tongue
and Powder basins were 117 and 118 percent of average, respectively.
Precipitation during March ranged from near to below average. The
upper Yellowstone River Basin received 155 percent of average precipitation
while the Lower Yellowstone River Basin reported 90 percent of average. The
Bighorn Basin received 148 percent of average precipitation while the
Wind River Basin received 88 percent of average. The Little Bighorn -
Upper Tongue Basin received 117 percent of average and the Powder River
had 65 percent of average precipitation.
March 2023 Yellowstone Mean Precip Oct-Mar WY2023 Yellowstone Mean Precip
Forecast stream flow in the Yellowstone Basin is below average
for the upcoming Spring and Summer. Stream flow for the
Yellowstone River above Sidney, Montana is forecast to be about
80 percent of average. Flow in the Tongue Basin is expected to be
84 percent of average. Flows in the Powder River are expected
to be about 76 percent of average.
Monthend storage at Boysen Reservoir was 98 percent of average.
Stored water in Buffalo Bill Reservoir was 105 percent of average.
Monthend storage was 96 percent of average at Bighorn Reservoir.
Yellowstone April 1, 2023 Spring and Summer Streamflow Forecasts
Platte Basin
The high elevation snow pack in the Upper North Platte Basin was
91 percent of average on April 1. The snow pack in the North Platte
Basin below Seminoe Reservoir was 116 percent of average. The snow
pack in the South Platte Basin was 111 percent of average.
Precipitation during March in the Upper North Platte Basin was 123
percent of average. In the Lower North Platte Basin, precipitation
was 56 percent of average. The North Platte Plains below Guernsy
Reservoir had 30 percent. The South Platte Mountains had 51
percent whereas the Plains had 68 percent of average March
precipitation.
March 2023 Platte Mean Precip Oct-Mar WY2023 Platte Mean Precip
Stream flow in the Platte Basin is forecast to range from
below to above average during the upcoming Spring and Summer.
Runoff for streams above Seminoe Reservoir are expected to be
about 150 percent of average. Streams in the South Platte
Basin above South Platte, Colorado can expect 70 percent
of average flow. For the remainder of the South Platte
basin, flows are expected near 75 percent.
Stored water in the South Platte Basin was 93 percent of average
on April 1.
North Platte Streamflow Fcst South Platte Streamflow Fcst
