Missoula National Weather Service Meteorologist Corby Dickerson sums up Montana’s winter of 2018/2019 this way.
"We started off the winter a little slow, then we accelerated. And then this month of February, historic in many ways, has been like we just slammed on the gas pedal and said, 'What spring? What mid-winter thaw?'.
Another Canadian cold front is now advancing across western Montana this evening. Unlike the system that left record snowfall in its wake earlier this week, Dickerson says this one is shaping up to be remembered for brutally cold temperatures.
"By the end of the weekend this will be the coldest Arctic air mass that we have seen this winter," he says.
This weather event will unfold in two phases. The first is already already playing itself out.
"Not a whole lot of new snowfall will be coming with this Arctic front. There's gonna be maybe an inch or so. It’s gonna be the wind and – as most people know – we have a lot more snow than normal on the ground. We anticipate the drifting of snow is going to be quite problematic in many places."
Lake County, for example, has issued an emergency travel only advisory for local roads through tomorrow. Officials are particularly concerned about slippery road conditions and reduced visibility.
The University of Montana in Missoula issued a rare weather statement this afternoon saying that while campus will likely be open Monday, people will need to protect themselves from the anticipated bone-chilling temperatures. Campus employees were urged to both prevent and report potential cold weather-related property damage.
An urban avalanche warning was posted yesterday on Missoula’s Mount Jumbo. The city issued a news release today saying the mountain’s snowpack appears to be stable for now. No further slides have been reported since Thursday.
But according to meteorologist Corby Dickerson, it’s impossible to know how avalanche conditions could be affected by all this wind and blowing snow:
"It’s gonna to be interesting. It’s one of those wildcard situations. I don’t think anyone truly knows exactly what’s going to happen, what’s going to cause it to break free if it does. Fortunately, not bringing in any more new snow is going to be a good thing, but the blowing and persistence of the east winds, that’s definitely going to be concerning."
Mount Jumbo remains closed to all human activity, and people are urged to stay off steep slopes on all mountains around the city. The city of Missoula recommends immediately reporting violators to 911.
Tonight’s temperatures across western Montana area will hover around the freezing mark. But the second phase of this cold front, which kicks in sometime late Sunday or early Monday will make those temperatures seem like child’s play.
"Many places 10 below, a lot of places 20 below; even 30 below seems possible in some of the colder locations like the Potomac Valley, could be in the Butte Valley, Anaconda. Even the Missoula Valley where our record is about minus 8, we should be flirting with breaking record low temperatures by Monday morning."
Those air-temperatures could be up to 35 degrees below seasonal norms. Wind chill factors could range from minus 30 in western Montana’s populated valleys to near minus 40 below zero along the divide.
"We’re certainly well aware that it’s prime calving season right now. We have a lot of young livestock out there," says National Weather Service Great Falls Meteorologist Paul Nutter.
"[Ranchers] definitely need to continue to take precautions to protect those young livestock. And people who are outdoors working, attending to those livestock certainly need to protect themselves. Be aware that frostbite can occur in around 10 minutes or less in those kind of conditions."
Nutter says ice jams continue to be a problem on many local rivers including the Missouri in southwestern Cascade County, the Madison River near Ennis and the Gallatin River near Logan in southwest Montana. No major flooding problems reported yet.
Ice jams are also likely to form on western Montana’s rivers. Missoula Meteorologist Corby Dickerson says the Bitterroot Valley flood potential is growing.
"The challenge we’re facing down there is there’s a lot of snow and there’s really going to be very limited places for the moisture to go."
Weather Service hydrologists are currently accessing the water content in the Bitterroot Valley snowpack to get a sense of the longer-term flood risk.
The immediate concern, however, is the anticipated record-setting bitter cold temperatures for the next several days. Corby Dickerson knows everyone’s sick of it, and offers these words of encouragement.
"Ultimately the sun will win. We’re moving closer and closer to the equinox, and it has a really, well, proven track record of winning. At some point it will win-out and the endless winter will be over."