Upper Missouri Basin
September precipitation across the Upper Missouri Basin was below average. Basin precipitation summaries for the Missouri Basin include: Milk St. Mary, 50 percent; Milk Canada, 45 percent; Lower Milk, 35 percent; above Toston, 99 percent; Toston to Ft. Peck, 76 percent.
Of the four major irrigation reservoirs in Montana; Lima Reservoir had 59 percent average storage, Clark Canyon was holding 73 percent of average water, Gibson Reservoir had 51 percent of average stored water, and Fresno Reservoir had 77 percent of average stored water.
Yellowstone Basin
Precipitation during September ranged from below to above average. The upper Yellowstone River Basin received 88 percent of average precipitation while the Lower Yellowstone River Basin reported 56 percent of average. The Bighorn Basin received 115 percent of average precipitation while the Wind River Basin received 138 percent of average. The Little Bighorn - Upper Tongue Basin received 116 percent of average and the Powder River had 102 percent of average precipitation.
Monthend storage at Boysen Reservoir was 102 percent of average. Stored water in Buffalo Bill Reservoir was 103 percent of average. Monthend storage was 95 percent of average at Bighorn Reservoir.
Platte Basin
Precipitation during September in the Upper North Platte Basin was 98 percent of average. In the Lower North Platte Basin, precipitation was 95 percent of average. The North Platte Plains below Guernsy Reservoir had 61 percent. The South Platte Mountains had 74 percent whereas the Plains had 74 percent of average September precipitation.
Stored water in the South Platte Basin was 114 percent of average on October 1.
