SANDPOINT — The U.S. Forest Service and National Weather Service issued avalanche warnings Friday for Bonner, Boundary and Shoshone counties.
The Forest Service’s Idaho Panhandle Avalanche Center said red flags began to fly amid snowfall and gusty winds in the Cabinet and Selkirk mountains ranges. Instability in the snowpack was also audible via whumphing, when the fracture of a lower snow layer causes an upper layer to collapse.
“With the continued precipitation and warming temperatures expect more weight and strain our persistent weak layers 2-3 feet down in the snowpack. Expect to see some natural avalanche activity and whumphing and cracking the next few days until things settle,” Eric Morgan said in a IPAC advisory.
The advisory urges against backcountry travel above treelines, where the slide risk is rated “high.” Avalanche risk near treelines is rated “considerable,” while slide risk in areas below treelines is rated “moderate.”
The slide problems are twofold.
Recent precipitation of 1-2 feet with winds and increasing temperatures have created storm slab formations on all upper elevations and exposed ridgetops. Shifty winds out of the southwest, west and northwest — in addition to Friday’s north wind — are helping to slab up areas and there is more snow expected today. Wind slabs and reverse loading are also concerns due to clocking winds, according to the center.
At 5,500 feet above sea level on a north aspect in the Selkirks, avalanche forecasters found 4 feet of snow with 2 feet of soft snow on surface hoar and faceted snow that sits on the Thanksgiving crust that is about a foot thick.
“Traveling in the mountains was challenging with a lot of trailbreaking and some downed timber off machine groomed trails.
The avalanche advisory, which remains in effect through midnight on Saturday, does not apply to local areas within the forecast region.
Keith Kinnaird can be reached by email at email@example.com and follow him on Twitter @KeithDailyBee.