The stage is set for Western Montana rivers to reach or exceed flood stage in coming weeks, largely because of a stubbornly high snowpack in the mountains.

“We can see that snowpack is not going anywhere” because of persistent cool weather, National Weather Service hydrologist Ray Nickless said Friday during a teleconference on flooding potential.

“There’s a lot of snow out there in the mountains ... and it’s pretty widespread,” Nickless said.

Snowpack in the mountains above the Flathead River Basin is 56 percent higher than the long-term average for this time of year and 38 percent ahead of last year’s snowpack.

The Kootenai River Basin snowpack is 45 percent above average and 26 percent ahead of last year’s levels.

“We’re still accumulating snow up in Glacier National Park on Flattop Mountain,” Nickless noted.

An automated snow gauge on Flattop Mountain shows 58 inches of snow water equivalent, which is 40 percent above normal for this time of year. That means that the 138 inches of snow at Flattop contain 58 inches of water.

Snow water equivalent is the amount of water contained within the snowpack. According to the Natural Resources Conservation Service, it can be thought of as the depth of water that would theoretically result if the entire snowpack melted instantaneously. 

Noisy Basin above the east side of the Flathead Valley has 54.5 inches of snow water equivalent in 125 inches of snow. The water in the snowpack is 29 percent above normal.

Throughout much of Western Montana, Nickless said, the snowpack is similar or higher than it was at this time of year in 2011, when there was significant flooding in some areas.

Despite the lack of snowmelt, Nickless said streams are currently running higher than average across Western Montana. However, National Weather Service hydrographs show Flathead-area rivers still are well below flood stage.

That could begin to change starting next week, when warmer weather is expected to settle in. It will take sustained warmth to melt the snowpack and get the runoff underway.

Like the Bitterroot and Clark Fork rivers, the mainstem Flathead River is forecast to “at least reach flood stage” at Columbia Falls in coming weeks, Nickless said.

“There may be a few other streams up there that we’ll have to keep an eye on like the Stillwater River,” he said.

The Stillwater is the only Flathead Valley river close to flood stage. It is running at 6.5 feet (flood stage is 7.5 feet) and is expected to remain a foot below flood stage in the coming week.

Reporter Jim Mann may be reached at 758-4407 or by email at jmann@dailyinterlake.com.