Repercussions from a mild winter, significantly less snowpack and the lack of precipitation throughout the state are showing the impacts of drought. The Bureau of Reclamation’s May forecast of the May through July water runoff predicted for the Bighorn River Basin shows reasons for forecast officials’ concerns.

The 2026 drought in Wyoming’s Big Horn Basin has resulted in one of the earliest and most severe seasons for water regulation in state history, driven by an abnormally dry spring and record-low snowpack according to the National Oceanic and Atmospheric Administration. A map issued by the NOAA shows the entirety of the Cowboy State in drought, with intensity categories ranging from abnormally dry to exceptional drought.

Only the east side of Yellowstone National Park comes close to normal precipitation, yet still is classified as abnormally dry. The mountains around the Absarokas and Bighorns are shown to be moderately dry, however, the largest percentage of the state, including the Powell area, is classified as suffering from severe drought or extreme drought. Counties to the east and south are dealing with the worst of the drought. A small area in south-central Wyoming is classified as exceptional drought.

The May through July inflow to Bighorn Lake is forecast to be approximately 407,000 acre-feet (af), which is 38% of the 30-year average of 1,061,000 af. Currently Bighorn Lake is 78% full.

In Cody, Buffalo Bill Reservoir’s May through July inflow to Buffalo is forecast at 450,000 af, which is 64% of the 30-year average of 705,000 af. As of May 1, Buffalo Bill is currently about 68% full.

In the Wind River Canyon area, the Bighorn and Wind rivers’ May through July inflow to Boysen Reservoir is forecast at 160,000 af, which is 29% of the 30-year average of 553,400 af. As of May 1, Boysen Reservoir was 71% full.

Bull Lake Reservoir’s May through July snowmelt runoff from Bull Lake Creek is expected to be 100,000 af, which is 72% of the 30-year average of 139,500 af. As of May 1, Bull Lake Reservoir is currently 33% full.

A reservoir is considered full when the pool elevation is at the top of active conservation or joint-use pools. The percentage is based on total reservoir volume below that level. Reclamation’s storage reservoirs in the basin have a combined storage capacity of 2.6 million acre-feet and most of that capacity is attributed to Bull Lake, Boysen and Buffalo Bill reservoirs in Wyoming and Bighorn Lake in Montana.

Areas of Wyoming have been hit hard and seen state action required. Back in February, the Wyoming State Engineer’s Office issued a “priority administration” order, requiring junior rights water holders along the North Platte River system to immediately cease diverting water. The order was expected to remain in effect through April. Snow drought, years of drought and low reservoir storage carryover were cited as the reasons for the emergency regulations. And, due to the dry conditions, four Wyoming counties — Hot Springs, Crook, Niobrara and Platte — are under a Stage 1 fire ban, which prohibits fireworks and open fires. Campfires were only allowed at residences and established campsites with a fire ring.

In Park County, the drought is sparking fears of fire and poor ag performance. The unseasonable warmth resulted in plants emerging from winter dormancy several weeks earlier than average, significantly greater than normal evaporation, increasing stress on soils even in areas that received near normal precipitation, and mountain snowpack peaking about a month earlier than average, according to a NOAA report.

Of course, the drought in the Northern Rockies affects other states dependent on mountain runoff for irrigation. Severe drought conditions and a lack of runoff from mountain snowpack in Wyoming have forced some western Nebraska farmers to drastically reduce production this year, including one Scottsbluff-area operation where just 60 acres will be planted out of its usual 1,000, according to a Monday KUVR Rural Radio report. The lack of irrigation water from Wyoming was an enormous concern, as was the long-term effect on groundwater supplies in the region.

The western Nebraska canals do not have water running in them as they usually do in May. Irrigation districts in the North Platte Project area were projecting only 30 to 40 days of canal water this year, compared to a typical 70 to 90 days. The three major irrigations districts were intending to fill canals on July 1. About 100,000 to 150,000 acres in Nebraska depend on irrigation water without wells as a backup supply.

For additional information on Buffalo Bill, Boysen, and Bull Lake reservoirs, contact Wyoming Area Manager Lyle Myler at 307-261-5671. For additional information on Bighorn Lake (Yellowtail), contact Montana Area Manager Ryan Newman at 406-247-7298.