The extreme weather pattern in Northwest Montana has left the Flathead Valley piled with snow, and has created backcountry avalanche hazards on peaks around the area.

As of 9 a.m. Sunday morning, more than 18 inches had piled up on the summit of Big Mountain in Whitefish, and 11 atop Blacktail Mountain in Lakeside.

Columbia Falls saw 14 inches of powder, and Bigfork had 12 inches. Even Glacier Park International Airport reported 6.1 inches of fresh snowfall.

This has created hazards in the backcountry, and the Flathead Avalanche Center is cautioning all backcountry skiers, snowmobilers and other outdoor enthusiasts to use extreme caution.

“Substantial new snowfall and wind drifted snow in the past 24 hours added a considerable stress to a previously weak snow pack,” the advisory reads. “Conservative decision making and terrain selection are essential today.”

Any ground above 6,000 feet in elevation, or on wind-loaded slopes, is considered high risk, and travel in those areas is not recommended.

In those high-risk areas, human-triggered avalanches are considered very likely.

The avalanche advisory is in place for much of Flathead County, but in particular everything to the west of Kalispell. All of Flathead, Lake and parts of Sanders counties are dealing with a Winter Storm Warning. Unnecessary travel is not advised.

Weather for Kalispell is forecasted to be bitterly cold for most of the week, with highs in single digits and lows dipping as far as 7 below zero.