January 1, 2020 Spring and Summer Streamflow Forecasts
Upper Missouri Basin
The high elevation snow pack in the Upper Missouri Basin as of January 1
was near to above average. The snow pack above Fort Peck, Montana was
109 percent. The snow pack in the St. Mary Basin was 110 percent, and the
Milk River Basin was 145 percent.
December precipitation across the Upper Missouri Basin was below average.
Basin precipitation summaries for the Missouri Basin include: Milk St. Mary,
58 percent; Milk Canada, 46 percent; Lower Milk, 77 percent; above Toston,
81 percent; Toston to Ft. Peck, 53 percent.
December 2019 Upper Missouri Mean Precip Oct-Dec 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 95 percent of average
April-September flows. Runoff is expected to range around
97 percent of average for the Missouri Basin above Fort Peck,
Montana.
Upper Missouri January 1, 2020 Spring and Summer Streamflow Forecasts
Of the four major irrigation reservoirs in Montana; Lima
Reservoir had 169 percent average storage, Clark Canyon was
holding 118 percent of average water, Gibson Reservoir had 43
percent of average stored water, and Fresno Reservoir had
151 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; 99 and 119 percent of average water, respectively.
Yellowstone Basin
The high elevation snow pack in the Yellowstone Basin was above average
on January 1. The snow pack in the Upper Yellowstone Basin was 94 percent
of average. The snow packs in the Wind, Bighorn, and Shoshone Basins were 91,
128, and 94 percent of average, respectively. The snow packs in the Tongue
and Powder basins were 109 and 128 percent of average, respectively.
Precipitation during December was below average. The upper Yellowstone
River Basin received 44 percent of average precipitation while the
Lower Yellowstone River Basin reported 50 percent of average. The
Bighorn Basin received 44 percent of average precipitation while the
Wind River Basin received 55 percent of average. The Little Bighorn -
Upper Tongue Basin received 50 percent of average and the Powder River
had 58 percent of average precipitation.
December 2019 Yellowstone Mean Precip Oct-Dec 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
100 percent of average. Flow in the Tongue Basin is expected to be
95 percent of average. Flows in the Powder River are expected
to be about 123 percent of average.
Monthend storage at Boysen Reservoir was 113 percent of average.
Stored water in Buffalo Bill Reservoir was 133 percent of average.
Monthend storage was 107 percent of average at Bighorn Reservoir.
Yellowstone January 1, 2020 Spring and Summer Streamflow Forecasts
Platte Basin
The high elevation snow pack in the Upper North Platte Basin was
112 percent of average on January 1. The snow pack in the North Platte
Basin below Seminoe Reservoir was 109 percent of average. The snow
pack in the South Platte Basin was 108 percent of average.
Precipitation during December in the Upper North Platte Basin was 105
percent of average. In the Lower North Platte Basin, precipitation
was 103 percent of average. The North Platte Plains below Guernsy
Reservoir had 146 percent. The South Platte Mountains had 85
percent whereas the Plains had 103 percent of average December
precipitation.
December 2019 Platte Mean Precip Oct-Dec WY2020 Platte Mean Precip
Stream flow in the Platte Basin is forecast to be below
average during the upcoming Spring and Summer. Runoff
for streams above Seminoe Reservoir are expected to be
about 93 percent of average. Streams in the South Platte
Basin above South Platte, Colorado can expect 92 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 115 percent of average
on January 1.
North Platte Streamflow Fcst South Platte Streamflow Fcst
