Drivers were urged to use extreme caution and only venture out on roads near Missoula if absolutely necessary on Friday as an Arctic cold front bore down on western Montana.
Midafternoon Friday, Missoula County issued a MEANS Alert for Interstate 90 for emergency travel only from Bonner east to Granite County. According to the Missoula County Sheriff's Office Facebook page on Friday afternoon, the warning was due to slick roads and blowing snow creating poor visibility and hazardous driving conditions.
The Ravalli County Sheriff's Office issued a warning of its own later in the day, saying road conditions were deteriorating quickly, with black ice and slush making for hazardous driving.
According to the Montana Highway Patrol's incident report page, there were two crashes on I-90 on Friday, both at mile marker 95, which is near the Wye.
Leeann Allegretto, a meteorologist with the National Weather Service in Missoula, said the Missoula County Sheriff's Department told her a combination of snow and ice on the road, combined with a high volume of wrecks, caused them to get in touch with her office.
"Right now, winds are a factor," she said Friday afternoon. "Visibility isn't too much of a factor according to the Montana Department of Transportation when we spoke to them. But winds will increase tonight and so will snow drifts."
Although the snow was supposed to stop Friday night, the Weather Service said it would be followed by winds of up to 20 or 25 mph with gusts of up to 35 mph through Hellgate Canyon and on I-90 east of Missoula.
"Once we get rid of the snow, winds will increase tonight and so will snow drifts," Allegretto said. "So once we get rid of one problem we pick up a new one."
Winds were expected to be strongest around 8 or 9 p.m. Friday, when an Arctic cold front was to drop down over Missoula. The winds were expected to taper off Saturday.
"With the winds, we are expecting a wind chill of close to zero degrees overnight," Allegretto said. "That will be another issue once we get rid of the snow. The wind chill for Butte and the Philipsburg area could well be into the negatives on Sunday."
The temperatures in Missoula will be in the teens for the high on Saturday, then drop down to a high of 10 on Sunday before warming back up again to the 20s on Monday, Christmas Day. The lows will be anywhere from 5 above to 10 degrees below zero during that time.
The West Central Montana Avalanche Center put out a “considerable” danger warning on Thursday, and will update that advisory on Saturday. In between, a new policy requires the center to post “No Danger Rating” messages on its website. Center analyst Tim LaRoche said that doesn’t mean it’s not dangerous, however.
“With the amount of snow that’s coming down, the avalanche danger could remain high,” LaRoche said Friday. “There’s a significant weak layer out there with lots of new snow on it.”
The center updates its posts every Tuesday, Thursday and Saturday. In between, it adds reports of conditions around the Missoula area, and adjusts its trend gauges accordingly.
LaRoche said anyone getting new backcountry ski or snowshoe gear would be well-served to get familiar with the center’s reports and even take an avalanche safety course.
“Right now, be conservative in your decision-making and go to places where you’re not exposed to avalanche danger,” LaRoche said. “It’s not uncommon to issue high-danger warnings this time of year and going forward.”
The latest information from the West Central Montana Avalanche Center can be found at missoulaavalanche.org/.