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Amid Historically Dry Spring, Flathead Lake Below Normal Pool Levels

NorthWestern Energy officials alert federal regulators of possible pending drought and decreased outflows

By Dillon Tabish

Following one of the driest springs on record in Kalispell, Flathead Lake is two feet below its full pool, threatening drought response by the managers of Kerr Dam, and forecasters are predicting an intense fire season.

There were 0.46 inches of precipitation in April and May in Kalispell, 1.61 inches below normal, according to the National Weather Service. The all-time low for the two-month period was 0.40 inches in 1924, and this year’s total will rank as the second driest on record since 1899. The month of May has seen only 0.11 inches of rain in Kalispell. With only two days left in May, this year is on pace to break the all-time monthly low of 0.23 inches in 2001.

The mountains are equally dry, with the Flathead River basin reporting only 55 percent of its normal snow levels. The Kootenai River basin is reporting 16 percent of normal levels, according to the Natural Resources Conservation Center.

NRCS officials say Montana is experiencing an early and below-average runoff in streams after a mild winter.

As a result of the low snowpack and dry weather, Flathead Lake is sitting two feet below its full pool level. NorthWestern Energy, which manages Kerr Dam, alerted federal and tribal agencies on May 29 that the water levels are below initial projections and could miss the targeted level by June 15, affecting outflows this summer.

“It’s simply a recognition that we’re potentially looking at a drought year,” Claudia Rapkoch, a spokesperson with NorthWestern Energy, said. “Hopefully Mother Nature will cooperate over the next few weeks and we won’t need to exercise the drought management plan. We’re cautiously optimistic that things will turn around and we’ll be able to get to full pool by June 15.”

The projected runoff forecast indicates that achieving the inflow necessary to fill the lake may be questionable. The current outflow of the lake is about 12,700 cubic feet per second (cfs). The lake elevation, as of May 29, was 2,891.01 feet, which is 1.99 feet from full elevation of 2,893.0 feet.

If the lake levels do not rise and drought conditions emerge, NorthWestern Energy would request a variance in its lake elevation and minimum flow levels. A drought management plan was filed with the U.S. Department of Interior in 2002, providing a strategy for managing modified lake levels and outflows.

The last time lake levels were below targeted amounts at this point in spring was 2010, when the dam’s former owner, PPL Montana, similarly notified the Federal Energy Regulatory Commission. Lake levels eventually rose that year and it was not necessary for the company to seek a variance for drought management.

The last time a drought management plan was implemented for Flathead Lake was in 2001.

The forecasted runoff for Flathead Lake from May through July is 62 percent of average, which has decreased from the 91 percent projection last month for the April to July period, according to the National Weather Service. The natural stream flow for the month of April was about 119 percent of average, but the stream flow for May has been only 64 percent of average.

According to the U.S. Drought Monitor, this corner of the state is abnormally dry.

The conditions don’t bode well for fire season.

The National Interagency Fire Center has predicted an above-normal fire season for this part of Montana.

It is likely the combination of these conditions will lead to an earlier than usual onset of both range and timber fires and that this will extend the length of the fire season in the Northwest, according to NIFC officials.

The potential for fires is already high and the season is expected to erupt in July and August.

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