Flathead Lake reaches full pool

Flathead Lake is effectively at full pool and Northwestern Energy, which owns Kerr Dam, won’t need to request a variance for meeting its federally required summer lake elevation by June 15.

However, Butch Larcombe, a spokesman for the utility company, said keeping the lake at that level could be a different matter.

“We’re confident we’re going to reach full pool and are probably not going to need to seek a variance from [the Federal Energy Regulatory Commission],” Larcombe said Tuesday. “But that doesn’t mean it always stays there. That’s going to be a challenge going forward this summer.”

The U.S. Geological Service’s gauge at Polson had the lake level at 2,892.93 feet on Tuesday afternoon.

Although full pool is 2,893 feet, the Tuesday number is within the margin at which the lake is considered full for the summer recreation season. Dam operators generally try to leave some wiggle room for major rain events that could temporarily raise water levels in the lake.

Larcombe blamed the lack of remaining snowpack in high elevations in the Flathead River drainage and record-breaking heat for driving uncertainty over whether the dam operators will be able to maintain the summer level until Sept. 1.

According to the National Weather Service’s Missoula office, the rain gauge at Glacier Park International Airport has registered 0.6 inches of rain so far in June, typically the wettest month with an average 2.56 inches of precipitation.

Since Jan. 1, the Flathead Valley has received 6.36 inches of precipitation, almost an inch below normal.

The dam’s license also includes mitigation measures for drought years, in which the dam operator can seek permission from local stakeholders to keep the lake below full elevation and also work with the federal Bureau of Reclamation to receive additional water from Hungry Horse Dam. On May 27, NorthWestern Energy sent a letter to the heads of the Federal Energy Regulatory Commission and the Department of the Interior, notifying the agencies that drought conditions are possible in the coming months.

Should those conditions be met, the utility could ask to lower the lake levels by up to one foot. The last time the lake failed to reach the target summer elevation was in 2001.

Reporter Samuel Wilson can be reached at 758-4407 or by email at swilson@dailyinterlake.com.