Avalanche forecast

Swan Range

Flathead Avalanche Center
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Avalanche danger

Tue
Alpine
2 · Moderate
Treeline
1 · Low
Below
1 · Low
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Highlights

Pay close attention to wind drifted snow and small loose dry avalanches while braving today's arctic air. Varying wind directions have left slabs of drifted snow on multiple aspects over the past week. Shooting cracks and pillowy-looking surfaces are clues to change aspects and search for safer snow.

Avalanche problems

  • Wind Slabs

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

    Roughly 3 to 5 inches of new snow fell yesterday throughout the Swan and the Whitefish Range. This fresh snow is masking an older, stubborn wind slab on the east and south aspects. In isolated areas, you may find this new snow blown into small, reactive slabs of drifted snow on all aspects. While seeking out powder snow in terrain sheltered from winds, manage your sluff and watch for long-running loose dry avalanches in consequential terrain.

    (12/23/2021)

    An FAC Forecaster team triggered this small, soft slab of drifted snow on a mid-elevation leeward slope in the southern corner of Glacier National Park.

    Photo: Nelson

Avalanche Discussion

Wind chill values will hover around -20 to -30 today. Make conservative and simple trip plans because a small error can leave you in a life-and-death situation.

Recent observations from the Swan, Whitefish, and Flathead Ranges mostly describe a loose dry avalanche hazard. Observations before Christmas Day describe stiff, hollow wind slabs and reactive cornices on aspects that face south and east. This trend left us with cold, dry snow resting on top of a stubborn, hard wind slab. Identifying these slabs may be more challenging today if winds remain light and no active wind loading occurs. If your decisions lead you into steep terrain, hedge your bets by selecting terrain sheltered from the wind. Be especially wary of aspects that face south, east, and north as you near the middle and upper elevation band. On these aspects, it is unlikely, but not impossible, to trigger one of these old, hard wind slabs that can be large enough to bury and injure you. 

In the past 24 hours, north and east winds got funneled across the divide and through valleys. These winds drifted snow onto westerly and southerly aspects while leaving other areas untouched by winds. This morning, remote weather stations show shifting winds back to the southwest. Expect to find a more reactive wind slab on various aspects and elevations today. Manage this new generation of drifted snow by paying attention to surface clues, such as shooting cracks and active wind transport. Freshly formed drifts should be relatively small and easy to manage. In areas where you do not see active wind loading, utilize defensive riding strategies by managing your sluff in steep terrain. 

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