Avalanche forecast

Swan Range

Flathead Avalanche Center
View on map

Avalanche danger

Wed
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
Open full map
Out of date — this forecast expired 5 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Watch for isolated slabs of drifted snow below ridgelines and in cross-loaded gullies further down-slope. These slabs will likely be reactive to the weight of a human, but relatively small in size. They will be more dangerous above timbered slopes and cliff bands. Stick to slopes sheltered from the wind and move to terrain with lower slope angles if you see shooting cracks around your skis or sled. 

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2

    Less than expected snow fell in the Swan Range with snow totals showing roughly 3 inches at the Noisy Basin weather station. Moderate to strong southwesterly winds blew new snow into slabs on the leeward side of ridges and gullies. Avoid these areas and stick to wind-protected areas. Slabs in wind drifted areas may propagate wide distances or may be triggered remotely. Today, winds will shift to the northeast and may transport snow onto unusual aspects. Plan your travel to not expose yourself to wind loaded aspects and watch for signs of shooting cracks around your skis or board. 

    (1/31/2022)

    A ski cut triggered this soft slab on a convex roll at 5250 ft in John Stevens Canyon. 

    Photo: blase reardon

Avalanche Discussion

The best advice I can offer is to make simple travel plans. New snow, shifting winds, and wind chill values of -40 tonight all contribute to a potentially complicated day. Keep slope angles low and avoid wind-loaded aspects all together. New snow and wind transported snow is falling on weak faceted snow, surface hoar, windboard, or a slick melt-freeze crust. On Monday, a rider in the southern Whitefish Range found cracking and slabs releasing in areas protected from the wind (observation). These likely failed on a weak layer of surface hoar or facets. Slabs releasing on these weak layers can propagate wide distances, be remotely triggered, or may not trigger until you are in the middle of the slope. Shooting cracks and whumpfing collapses are signs you found this problem.

Though the storm was a bit late to the party, it still packed a punch throughout most of the forecast area. Tunnel Ridge in the Flathead Range saw roughly 14 inches, Whitefish Mountain Patrol reported 11 inches at their mid-mountain station, and Stahl in the northern Whitefish Range shows roughly 8 inches of new snow. Coming in last was the Swan Range where only 3 inches of new snow is being reported at the Noisy Basin station.

This healthy shot of snow was accompanied by wind speeds averaging in the upper teens and low twenties with gusts reaching 50 mph out of the southwest. This transported snow into slabs one to three feet thick on the leeward side of exposed ridgelines. A curveball will get thrown this afternoon with increasing winds out of the north and east. Wind speeds are expected to gust to 50 mph, drifting snow onto slopes that face west and south. Travel cautiously and bring extra layers today.

Regions covered