Unseasonably cold and wet weather is set to pummel Montana this weekend. The cold snap’s widespread impacts could possibly affect power lines, livestock and backcountry travelers. The next several days will make it feel like we bypassed autumn altogether and went straight to winter.
Missoula National Weather Service meteorologist Jenn Kitsmiller summarizes the inbound winter-like weather event with one word: ‘abnormal’.
"Here in Missoula it’s been 30-plus years since we’ve seen measurable snow in September."
That could change this weekend. In fact, the entire state will bear the brunt of this cold front. Kitsmiller says the system will unfold in three distinct phases. The first lays down its cards Friday evening into Saturday morning.
"This is going to be the period when we’re expecting to see some high-elevation heavy, wet snow; particularly along the Continental Divide – Marias Pass in particular," says Kitsmiller.
Forecasters say up to a foot of snow could accumulate there. The valleys, meanwhile, will see rain during this same Friday/Saturday window. Wind too – especially in northwest Montana, where north/northeast gusts could reach 50 miles-per-hour.
"With that we have quite a bit of concern with those winds to see some tree and powerline damage," says Kitsmiller. "We’re also concerned about dock and boat damage on Flathead lake."
The storm system’s second phase grabs hold Saturday night into Sunday morning. That’s when the valley rainfall could change over to wet, heavy snow. Several inches are possible, but ground temperatures are still fairly warm, which could prevent much accumulation on roads.
Kitsmiller says "one thing we’ll be concerned about in this time frame is that heavy, wet snow on trees, potentially bringing down branches and causing issues with power."
The third and final phase of the early season winter storm on Monday and Tuesday will be punctuated with overnight lows in the 20’s, perhaps even the teens. The hard freeze could damage irrigation systems, be tough on livestock and create slippery, dangerous driving conditions.
The wintery forecast has prompted Glacier National Park to announce some temporary closures. The Many Glacier Campground closed Thursday and the Two Medicine Campground will close Friday.
Deputy Superintendent Pete Webster says most of Going to the Sun Road also shut down in anticipation of this weekend’s storm.
"Currently, the Going to the Sun Road is closed between Jackson Glacier Overlook on the east side and Avalanche Campground on the west side," says Webster.
Webster says all roads on the east side of the park are expected to close Friday as snow begins to fall. He adds that the park is working to get seasonal employees out before then.
"We’re going to have less employees out there to help folks if they get into trouble," he says. "We certainly, like everybody else, are encouraging folks to not enter the area during the course of the storm."
The closures on the east side of the park are expected to last through at least Tuesday.
Road preservation work on the western portion of Going to the Sun Road will prevent plows from working between Avalanche Campground and Logan Pass. The section of road was expected to re-open Sunday, but Webster says that date will now depend on if and when the snow melts.