The Flathead County Sheriff's Office has issued an emergency travel only warning for Flathead County roads effective at 8:50 a.m. Friday morning, Jan. 2.

"The County Road Department is aggressively plowing the county roads, however until this storm breaks, please do not travel," Flathead County Sheriff Mike Meehan wrote in the warning notice.

The foot or so of new snow overnight has also made conditions dangerous high above the valley, where the United States Forest Service and Glacier Country Avalanche Center have raised avalanche warnings to "High" across the mountains of Northwest Montana.

Locations in the East and West Cabinet Ranges on the Kootenai and in the mountains around the Flathead and Mission valleys registered 0.4-0.8" of new snow water equivalent loading, in a 9-hr period Thursday night and into early Friday morning, according to Stan Bones, with the Flathead National Forest. This heavy new snowfall combines with 4-5" of new snow water equivalent received over the last seven days. The new snowfall over the last week has begun to completely bury the vegetative and terrain anchors that were widely existing earlier.

The new snowfall is building a more consolidated, dense, slab layer which is now sitting atop the weakly bonded and lower density snow received earlier in December. Conditions have combined to produce an unstable, inverted snowpack with higher density surface snow over-topping less dense, more weakly bonded buried snow, he said.

Both natural and human triggered avalanches are likely. Very dangerous avalanche conditions exist. Travel in avalanche terrain is not recommended. Extensive skill, experience, and local knowledge are essential to safely travel in the backcountry currently.

The weather forecast is for snowfall to continue Friday, bringing a total of 6-12" of new snow depth to the valleys and mountains of NW Montana. Temperatures are expected to drop into the teens and single digits Friday night and Saturday as colder air moves in behind the Pacific front. Mountain winds are forecasted to be moderate through the weekend, blowing 5-15 MPH, mostly from the W-SW. These conditions should maintain the avalanche danger at an elevated level through the weekend.

The avalanche advisory will be updated on Tuesday, Jan. 6.