Flathead Lake Levels Could Drop 2 Feet Below Full Pool by July
Hot and dry conditions have caused a rapid runoff this spring, leading to low streamflows and forecasted levels well below full pool on Flathead Lake
By Maggie Dresser
Officials today announced Flathead Lake could drop to nearly 2 feet below its full pool of 2,893 feet by Fourth of July weekend if unseasonably hot and dry conditions persist in northwest Montana, according to Energy Keepers, Inc. (EKI), the tribally owned power producer that oversees hydroelectric operations on the lake.
According to a Tuesday morning news release from Energy Keepers CEO Brian Lipscomb, Séliš Ksanka Ql’ispé (SKQ) Dam operators in Polson are filling Flathead Lake as aggressively as possible while avoiding flood control limits to meet license required minimums.
An early spring runoff in the Flathead River basin has prompted low streamflows, which will keep Flathead Lake well below full pool this summer. According to current forecasts, the lake will reach its maximum level for the year at 2,891.9 feet around June 15 when the inflows are expected to go below the minimum outflow requirement, which will cause the lake levels to decrease. Levels could reach 3 feet below full pool in August.
The Flathead River basin’s snow water equivalent (SWE) levels on June 10 were 59% of normal, according to U.S. Department of Agriculture (USDA) data.
Below-normal precipitation this spring has contributed to the decreased water supply, which hovered around 70% of normal in April and May followed by significantly below-normal precipitation so far in June.
Flows are currently at 50% of normal on the Middle and North forks of the Flathead River, which account for 60% of the inflow to Flathead Lake.
The forecast marks the third year in a row of hot and dry conditions that have impacted Flathead Lake’s levels. If conditions continue this year, 2023, 2024 and 2025 will be the driest consecutive years on record in the Flathead River basin, which dates back to 1949.
According to the Northwest River Forecast Center, the water supply volume in 2023 was 64% of annual average while the water supply in 2024 was 74%. In June 2022, record high precipitation occurred in the basin, which brought Flathead Lake 0.7 feet above full pool.
To prepare for the diminished water supply, Energy Keepers, a corporation of the Confederated Salish and Kootenai Tribes (CSKT), this spring began coordinating with its partners and has implemented the license-required drought management plan, according to officials.
The U.S. Army Corps of Engineers on March 13 approved a flood risk management deviation request to allow as much runoff as possible to be captured, bringing lake elevations to 3 feet from full pool on May 26. Minimum flows have been maintained ever since.
Lakefront boat storage and dock access may be affected if water level forecasts are realized. So far, June has been significantly below normal and the 10-day weather forecast shows continued below normal chance of precipitation.
“While recreational boating and fishing can continue at any lake elevation with the accessible public boat ramps, lake users should be aware that lakefront boat storage and dock access may be affected if these water level forecasts are realized,” according to the release from EKI. “As forecasts are updated through the months of June and July, EKI will update the public to any changes.”
Updated forecasts on Flathead Lake levels, including inflows and outflows, are available on EKI’s website here.