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Bureau of Reclamation

06/12/2026 | Press release | Distributed by Public on 06/12/2026 14:19

Snowmelt forecast for Bighorn River Basin

WASHINGTON - Reclamation's June Forecast of the June through July water runoff predicted for the Bighorn River Basin is as follows:

  • Bighorn Lake - Bighorn River June through July inflow to Bighorn Lake is forecast to be approximately 225,000 acre-feet (af), which is 30% of the 30-year average of 313,100 af. As of June 1, Bighorn Lake is 81% full.*
  • Buffalo Bill Reservoir - Shoshone River June through July inflow to Buffalo Bill Reservoir is forecast at 350,000 af, which is 68% of the 30-year average of 513,800 af. As of June 1, Buffalo Bill is 75% full. *
  • Boysen Reservoir - Wind River June through July inflow to Boysen Reservoir is forecast at 150,000 af, which is 36% of the 30-year average of 411,200 af. As of June 1, Boysen Reservoir is 71% full. *
  • Bull Lake Reservoir - June through July snowmelt runoff into Bull Lake Reservoir from Bull Lake Creek is expected to be 80,000 af, which is 73% of the 30-year average of 109,900 af. As of June 1, Bull Lake Reservoir is 47% full. *

*Reservoir is considered "full" when the pool elevation is at top of active conservation or joint-use pool. The percentage is based on total reservoir volume below that level.

The Bighorn Basin is a plateau region and intermontane basin, approximately 100 miles (160 km) wide, in north-central Wyoming. It is bounded by the Absaroka Range on the west, the Pryor Mountains on the north, the Bighorn Mountains on the east, and the Wind River and Granite Mountains on the south. It is drained to the north by tributaries of the Bighorn River, which enters the basin from the southwest, and passes through a gap between the Owl Creek and Bridger Mountains as the Wind River before changing its name to the Bighorn River at Wedding of the Waters, south of Thermopolis.

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. Hydropower is produced at Boysen Powerplant and four powerplants supplied by Buffalo Bill Reservoir in Wyoming and at Yellowtail Powerplant in Montana.

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.

Bureau of Reclamation published this content on June 12, 2026, and is solely responsible for the information contained herein. Distributed via Public Technologies (PUBT), unedited and unaltered, on June 12, 2026 at 20:19 UTC. If you believe the information included in the content is inaccurate or outdated and requires editing or removal, please contact us at [email protected]