Avalanche forecast

Swan Range

Flathead Avalanche Center
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Avalanche danger

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

Light snow showers and increasing winds may form thin slabs of wind-drifted snow this afternoon at upper elevations. Blowing snow, pillow-like features, and a denser snow surface are signs the wind is at work.  Cracking underneath you or your machine indicates instability. The hazard will rise overnight as the snowfall increases. 

Avalanche problems

  • Wind Slabs

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

    Increasing southwest winds and light snowfall may form thin slabs of wind-drifted snow on leeward slopes later today. Slab development will depend on the arrival and quantity of new snow. These features are found downwind of ridgelines, saddles, tree stands, and rock outcroppings.  Sidewalls of cross-loaded gullies can accumulate substantial drifted snow. 

    Blowing snow points in the direction of fresh slab development. Dune-shaped or pillow-like features identify areas of wind-drifted snow. Cracking in the snow surface indicates instability directing you to lower-angle or terrain sheltered from the wind. 

    (12/2/2024)

    This is an example of a small wind slab at a mid-slope location. Slabs tend to be larger and more dangerous near ridgeline elevations. 

    Photo: Flathead Avalanche Center

Avalanche Discussion

Warm Pacific moisture arrives today and increases overnight. The timing and quantity of precipitation will dictate when the avalanche danger rises. We expect the hazard to creep up by this afternoon, especially in the Whitefish Range, where up to 6 inches may fall by sunset. Most snowfall may only occur during the overnight hours, and our confidence is higher that the danger will increase by Sunday morning, especially in the favored Swan Range. 

Snowfall will add weight to the Whitefish Range, Flathead Range, and Glacier Park buried surface hoar. Avalanches on this layer occurred in the central and northern Whitefish Range during the heavy snow event of 12/7-12/8, but other locations received much less loading. This weekend's storm contains much less water than that event, and we don't anticipate widespread natural avalanche activity. However, the chance for a human-triggered slide may increase as many slopes lack a slab above the weak layer. This storm and warm weather may form the missing ingredient. 

We have bumped the danger up and added a Wind Slab problem at upper elevations to the Swan Range. Southwest winds are increasing and impressively robust at the Aeneas Ridge wind station, which averages 30 mph with gusts of 55. More snow is needed for transport due to the lack of recent snowfall. If this problem develops, it will be towards the end of the day. We expect slabs of wind-drifted snow to be more of an issue overnight and tomorrow at mid and upper elevations. 

Did you hear about the app? You can now access our region's forecasts, observations, and weather data directly from the Avy App (IOS; Android). Many features are accessible offline, so you can win debates about the avalanche problems right in the backcountry or submit an obs while driving home. 

Are you looking for avalanche education opportunities? Check out our calendar for upcoming events. Next week, there is an Avalanche Awareness Class at Bias Brewing on Monday, December 16th.

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