A rare and potentially historic winter storm is expected to bear down on Western Montana this weekend, bringing damaging winds and several inches of snow to most valley locations.

“This is something that is definitely very abnormal for this time of year,” warned meteorologist Jenn Kitsmiller with the National Weather Service in Missoula. In a press briefing Thursday, Kitsmiller noted that Missoula has not received snowfall in September since 1983.

The storm will hit the area in three phases, Kitsmiller said, beginning with gusty winds and rain, followed by snow and then near-record cold temperatures.

The first punch is expected Friday night into Saturday morning. Heavy snow, with potential for blizzard conditions are anticipated for mountainous terrain, especially along the Continental Divide. More than 2 feet of snow is possible for places like Marias Pass along U.S. 2 south of Glacier National Park.

Road closures were put in place across Glacier National Park on Thursday in preparation for the storm.

Going-to-the-Sun Road from Jackson Glacier to Logan Pass closed Thursday morning. The Many Glacier Campground was to close at noon Thursday, while the Two Medicine Campground was to close Friday morning. The St. Mary Campground will remain open but “camping not advised” signs were in place.

The Flathead Valley is expected to see a cold rain during this period, but dangerous winds, with gusts of 50 mph or higher, are possible. This could knock over trees and damage power lines in valley locations. Widespread power outages are possible.

Residents are advised to fasten loose objects or shelter objects in a safe location prior to the onset of winds.

Flathead Lake could see dangerous waves that could cause boat and dock damage. Kitsmiller noted that a similar storm hit the area in September of 2000 that stirred up 10-foot waves and sunk multiple boats.

Saturday night into Sunday, the rain will transition to wet snow in the valley. Warm ground temperatures will limit accumulations, but a few inches are possible on grassy surfaces and some roads.

Snow totals in Polson could be in the 3-4 inches range, Bigfork 2-3 inches, Kalispelll 1-2 inches, Columbia Falls 2-3 inches, Libby 1-2 inches and West Glacier 4-6 inches.

The snow will be wet and heavy, which could cause further damage to power lines and bring down tree branches.

By Monday, the main concern will be near-record cold temperatures. Lows in the Flathead Valley will dip into the 20s, while Polebridge, Yaak and Condon areas will see the teens.

These temperatures will likely cause damage to sensitive vegetation and exposed irrigation systems. People headed into the backcountry are advised to be prepared for deep snow and freezing temperatures.

The remainder of next week will see high temperatures about 20 to 25 degrees colder than normal for this time of year, the National Weather Service predicted.