Winter wallop headed for Flathead

The recent winter-weather dry spell is about to come to a screeching halt, as the Flathead Valley is on the cusp of the largest winter storm system of the season.

The National Weather Service on Sunday issued a winter storm watch for Northwest Montana, calling for heavy snow through Wednesday morning. Three-day snowfall totals across the Flathead Valley could be in the 8 to 12 inches range, with some high-elevation areas due for far more.

“The mountains are going to see a continuous stream of heavy, intense snowfall from now through [Dec.] 20,” said LeeAnn Allegretto, a meteorologist with the National Weather Service, in a Monday morning conference call

By Tuesday and Tuesday evening, almost every part of the Flathead Valley should be in the midst of the storm, Allegretto added.

Mountain terrain, including Marias Pass on U.S. 2, could see several feet of new snow. The Weather Service is predicted up to 50 inches in the mountains of Glacier Park.

The Weather Service in Missoula has been monitoring the storm for days. The system is sweeping in from the Pacific and is essentially shooting straight across the Pacific Northwest and will blanket much of Western Montana.

While the system has been anticipated for a while, recent developments have allowed the meteorologists to predict the severity of the storm with increased accuracy. Allegretto said temperatures should plummet across the Flathead to the point that all the precipitation will be coming in the form of snow rather than rain, Allegretto said.

The Weather Service predicts there is a 69 percent chance that Kalispell receives at least 6 inches of snow through Dec. 20, with that probably jumping to 99 percent in West Glacier and Eureka.

Snowfall rates across Northwest Montana could be in the 1 to 2 inches per hour range at the peak of the storm. Commuters should be prepared for dangerous travel with near-zero visibility.

“It’s still an evolving scenario, but we are expecting it to be pretty good, efficient snow-producing conditions,” Allegretto said. “By [Tuesday] we should be dropping to around freezing, and by Wednesday we will be full into it.”

The entire system has the potential to dump up to 18 inches on Kalispell, up to 24 inches in West Glacier and possibly a foot in Bigfork, according to data provided by the Weather Service.

Lesser amounts of 3 to 6 inches of snow are expected in the Mission Valley, with 2 to 3 inches possible in Missoula and anywhere between no snow up to 8 inches in Polson.

By Thursday the snowfall will cease in some areas, at which point a tide of cold air is expected to migrate south from Canada and settle in over the valley. Travel conditions could remain dicey for the holiday weekend.

Snow is expected to continue in the mountains, and wind gusts of up to 30 miles per hour are expected to rocket through the valley during that period. The wind chill is expected to drop temperatures well below zero in many areas, including Eureka and West Glacier, with conditions only slightly warmer in Kalispell.

Lows in the single digits and below zero are expected Friday and Saturday nights. Winds gusting to near 50 mph will be possible through Bad Rock canyon. Blowing the drifting snow could create hazardous driving conditions for Christmas Eve travelers.

The Weather Service says Christmas Day “could be one of the coldest in many years.” Low temperatures will be below zero while high temperatures struggle to reach the single digits.

Reporter Peregrine Frissell can be reached at (406) 758-4438 or pfrissell@dailyinterlake.com.