Whitefish Range

Very dangerous conditions exist at all elevations. Large natural avalanches are likely at upper elevations; debris from these slides may run to low elevations. Triggered and natural wet snow avalanches are also likely on and below steep slopes at low and mid elevations, making even small slopes dangerous. Avoid travel in the backcountry, including slopes adjacent to ski areas.

Unless you're a glutton for punishment, it's not a good day to be wandering around the backcountry. Wet, windy, and very dangerous. And that follows several days of wet, windy, and dangerous. With more of the same on the way. It's a good day to spend time with family and friends, or tidy your garage. Maybe return that air fryer your aunt gifted you. 

As wet as it's been in the valleys since Christmas Eve, air temperatures at upper elevations have remained mostly below freezing, with strong southwesterly winds. Observers have reported blowing snow off ridgelines. The wind-blown snow has been deposited as thick slabs, particularly near the crests of the Whitefish, Swan, and Flathead Ranges. These slabs will grow today and tonight, increasing the likelihood of them releasing spontaneously and increasing the potential size of natural avalanches. Debris from these slides can entrain wet snow at lower elevations and run to valley floors. Avoid these runouts. Plumes of snow near ridges are clear signs of wind transporting snow above you.

Valley stations are reporting 0.7 to 1.5  inches of rain in the past 36 hours or so. That rain has fallen on a snowpack that, until Christmas Eve, consisted of dry, unconsolidated snow. Now it's what, in technical terms, is called mush. Gwanch. Or slop.And it's unstable, as evidenced by a wet loose avalanche that blocked one lane of Highway 2 near Stanton Creek Monday night, and avalanches reported near Marias Pass Monday.  The danger posed by these conditions continues today, though it will diminish after the cold front sweeps through tonight. Because wet snow avalanches may release near the ground, even small slopes and timbered areas can be dangerous. 

And then there are the weak facets buried Nov. 22 that produced triggered and remotely triggered avalanches the first week in December. Those facets aren't gone. They're undergoing all manner of rapid and unpredictable changes - rounding with the heat from the ground and rain, being strained by changes in the properties of the slabs above them, such as increased creep rates. The undertainty about these layers, including uncertainty about their distribution, is the key thing to keep in mind today. That uncertainty makes managing terrain and slope angles very tricky, because the likelihood of remotely triggering these layers may be increasing. The potential size of triggered and natural slides definitely has. 

And if that wasn't enough to keep you out of the backcountry.... We have reports of isolated glide cracks that have already formed, possibly because the ground wasn't frozen when the first snow fell. These cracks are likely to release with the warming and rain. One exists in Crown Bowl, in Noisy Basin. Getting buried by debris from a glide avalanche during the December holidays is not the way you want to make a name for yourself.

Sadly, the season's first avalanche fatality occurred Monday in Colorado. The avalanche caught four riders and buried two; one rider did not survive. The accident occurred on a steep slope within sight of a US Highway. Our hearts go out to the survivors, family, friends, and community of the victim. With the atmospheric river blasting across the western US, I fear this won't be the last this week. Don't make the news this way.