According to Natural Resources Conservation Service data, as of June 19, 2023, the southern Montana and northern Wyoming region received 5.29 inches of rain, which is 193% of the average total of 2.74 inches for the entire month of June. In response, releases out of Yellowtail Dam into the Bighorn River are scheduled to increase from the current release of 13,000 cubic feet per second to 15,000 cfs between June 20-22, 2023.  

The estimated safe channel capacity below Yellowtail Dam is 20,000 cfs, however inundation of low-lying areas adjacent to the river could occur. The last time releases to the Bighorn River were this high was during June 2011. Rain throughout the basin is expected to continue for the next several days and additional increases may be necessary.   

“Visitors to the Bighorn River should be mindful of fast-moving and cold water that can pose a potential danger to people recreating in the area. Please follow water safety recommendations like wearing a life jacket and never swimming alone,” said Montana Area Manager Ryan Newman. “While we understand increased flows may be a challenge to people who live adjacent to the river or are participating in recreation activities, we must emphasize the importance of managing reservoir operations for flood control and safety.” 

Please call the National Park Service at 406-666-9961 for more information about potential boat ramp closures.  

Reclamation will continue to release updated information concerning flow rates as they are evaluated and changed. For more information about Yellowtail Dam water supply and projected operations visit https://www.usbr.gov/gp/lakes_reservoirs/wareprts/main_menu.html

Original source can be found here