Hot weather means higher stream levels, more rain on the way

Higher temperatures forecasted by the National Weather Service for Saturday, Sunday and Monday, June 4-6, could cause rivers and streams in the Flathead to rise sharply by early next week.

Temperatures are expected to reach the upper 70s or lower 80s on Sunday and Monday, "the warmest temperatures we've certainly seen this year," meteorologist Bruce Bauck said.

But it could take a couple days for the warm weather to melt snow and bring it down to the level of rivers and streams at the valley floor.

Another weather system with heavy rain is expected by Tuesday, June 7, but it's not expected to include colder temperatures as this past week's weather pattern. Monitors in Whitefish recorded 1.59 inches of rain this past week, while Bigfork got 2.04 inches.

The heavy rain at the valley floor this past week fell as more snow at the higher elevations. At Noisy Basin, 6,040 feet up on the Swan Range at the trailhead to the Jewel Basin, the automated snow-measuring site recorded 3.6 inches of precipitation on Wednesday and Thursday, June 1-2.

The snow depth at Noisy Basin is now 143 inches, which translates into 73.2 inches of standing water. That is 257 percent above the average snow-water equivalent of 28.5 inches.

Across the Flathead River drainage, the snow-water equivalent at higher elevations averages 226 percent of normal.

The "worst-case scenario" for flooding in the Flathead, according to Bauck, would involve a full week of very warm weather followed by a significant rain system - similar to what happened during the 500-year flood in 1964. But that's not in the forecast, Bauck said.

The Flattop Mountain automated snow-measuring site, in Glacier National Park, reports 138 inches of snow, which is 60 inches of snow-water equivalent and about 169 percent above normal.

Significant avalanches in the Park since Memorial Day have made plowing difficult for crews on the west side of the Going-to-the-Sun Road. More than 2 1/2 feet of new snow has fallen on avalanche paths above the alpine sections of the Sun Road, and plow crews have encountered debris piles up to 10 feet deep.

Park officials anticipate higher water levels in Park rivers and streams for a longer duration than normal, with some reaching flood stage. Officials caution visitors about the dangers posed by the unusually high water. Drowning is the number one cause of accidental death in the Park.