NRCS publishes May water supply outlook

On May 1, the U.S. Department of Agriculture’s Natural Resources Conservation Service (NRCS) published the May 2026 Wyoming Basin and Water Supply Outlook Report, which analyzes snowpack, precipitation, streamflow and reservoir storage across the state of Wyoming. 

The report assesses the water supply outlook for the entire state of Wyoming, as well as individual basins including the Snake River, Madison Headwaters, Yellowstone River, Wind River, Big Horn River, Shoshone River, Powder River, Tongue River, Belle Fourche River, Cheyenne River, Upper North Platte River, Lower North Platte River, Laramie River, Sweetwater River, South Platte River, Little Snake River, Upper Green River, Lower Green River and Upper Bear River basins.

Snowpack and precipitation

According to NRCS, snow water equivalent (SWE) across the state of Wyoming was 38 percent of median as of May 1, compared to 72 percent of median at the same time last year.

The highest SWE was reported in the Yellowstone River Basin at 90 percent of median, and the lowest was reported in the Belle Fourche and Lower North Platte river basins, both of which posted a SWE at four percent of median.

The report also shows the Belle Fourche River, Cheyenne River, Laramie River, Little Snake River, Lower Green River, Lower North Platte River, Powder River, South Platte River, Sweetwater River, Upper Bear River and Upper North Platte River basins were below 50 percent of the median SWE recorded from 1991 to 2020.

Additionally, NRCS notes the Madison River Basin saw the highest precipitation over the month of May at 145 percent of median, while the Belle Fourche River Basin saw the lowest amount at 64 percent of median.

Streamflow yields

For median streamflow yields, NRCS expects all Wyoming basins – except the Upper Green, Lower Green, Little Snake and Cheyenne river basins – to average 57 percent from May through September. 

Streamflow yields for these four exceptions are expected to average 55 percent, 54 percent, 35 percent and 21 percent, respectively, from May through July. 

Expected streamflow yields for individual basins across the state include the Shoshone River Basin at 93 percent of median, the Yellowstone River Basin at 89 percent of median, the Snake River Basin at 79 percent of median, the Wind River Basin at 68 percent of median and the Big Horn River Basin at 65 percent of median.

NRCS predicts streamflow yields for the Tongue River Basin, Powder River Basin, Upper North Platte River Basin, Laramie River Basin, Lower North Platte River Basin and Sweetwater River Basin will respectively report 58, 54, 38, 37, 32 and 31 percent of median.

Reservoir storage

For the entire state of Wyoming, NRCS expects average reservoir storage at 88 percent of median, down from 94 percent at the same time last year. 

The majority of reservoirs reported numbers below median including those in the Upper Bear River Basin at 42 percent, the Laramie River Basin at 47 percent, the Upper North Platte River Basin at 57 percent, the Cheyenne River Basin at 74 percent, the Belle Fourche River Basin at 86 percent and the Lower North Platte River Basin at 89 percent.

Reservoir storage in the Wind River Basin was near median at 91 percent, as was storage in Lower Green River Basin reservoirs and the Boysen Reservoir in the Big Horn Basin, both of which posted numbers at 96 percent of median. 

The Buffalo Bill Reservoir on the Shoshone, as well as the Upper Green River and Snake River basin reservoirs reported numbers above median at 112 percent, 117 percent and 122 percent, respectively.

Hannah Bugas is the managing editor of the Wyoming Livestock Roundup. Send comments on this article to roundup@wylr.net.