Bulletin d’avalanche

Swan Range

Flathead Avalanche Center
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Danger d’avalanche

Wed
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
3 · Marqué
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Périmé — ce bulletin a expiré 2 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Dangerous avalanche conditions exist.  A natural or human-triggered avalanche will run long distances and will entrain a substantial amount of snow. Enjoy the excellent riding conditions by sticking to lower-angled slopes and staying out from under steep slopes.

Problèmes avalancheux

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1.5–3

    You're likely to trigger an avalanche involving new and recent snow in steep terrain today. Avalanches in the new snow may release as slabs, or as loose dry avalanches. Both of these avalanche hazards will entrain enough snow on the way down to bury, injure, and kill a person. Wind speeds have remained in the single digits with some gusts into the low 20s, so expect only isolated slabs of wind-drifted snow just downwind of ridge crests.

    Manage new snow avalanche problems by sticking to slopes with lower slope angles. I also don’t recommend walking or riding in the tracks or runouts of large avalanche paths. A substantial amount of snow fell, and any avalanche will entrain a lot of snow and run long distances.

    (12/28/2024)

    Crown of a skier-triggered soft slab in the Canyon Creek area, adjacent to WMR.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    2–3

    Recent storm totals are stressing weak layers buried 2 to 4 feet deep. Avalanches that fail on these layers can be released by debris from avalanches involving the new snow, or by a rider on steep slopes. Common trigger points are steep rollovers or spots where the snowpack is thinner. An avalanche failing in the old snow will be difficult to escape and potentially deadly.

    Avoid this problem by sticking to slopes with lower slope angles and avoid traveling in the runouts of large avalanche paths. Give the snowpack time to adjust before stepping out into steep terrain.

    (12/30/2024)

    A rider triggered avalanche that failed on facets buried in mid-December. 

    Photo: Cam Johnson

Avalanche Discussion

There is much to celebrate today: New Years, new snow, cool temperatures, and light wind. The combination of it all can make for a wonderful day in the mountains IF you manage the terrain correctly.

Celebrate the new powder snow by sledding in gladded meadows or sliding down slopes with lower slope angles that are free of overhead hazards. Be especially conservative in your terrain selection if you head into the Flathead or Swan Ranges, where the recent storm exceeded forecasted snow totals. The snowfall over the past 48 hours in Noisy Basin is in fact a record for December at that site, and exceeded to 100th percentile for the model forecasts Monday morning. In the Whitefish Range, precipitation tapered off sooner, and less snow fell, which is the reason for a Moderate Danger rating in that forecast zone.

This weekend, human-triggered avalanches plagued the southern Whitefish Range. Although observations from yesterday (Monday) suggest the snowpack is gaining strength, we are still within a time window that these recent slides should be a key consideration in your terrain selection.

Observations from Monday in the Flathead and Swan Ranges generally describe a Loose Dry avalanche problem. An experienced rider was able to push down some sluff that entrained enough snow to knock someone off their feet. As the storm snow settles and consoidates, triggering slab avalanches involving the new and recent snow will become the primary consideration.

The snowpack is not yet over a stress test in parts of the forecast area. Give it time to heal before venturing out into steep terrain.

Downloaded the app yet? 

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 doublecheck danger ratings and travel advice on the drive to the trailhead or in the backcountry. 

Events and Education:

Want to start your New Year on the right foot? Sign up for a Partner Rescue Clinic for motorized Riders on January 4. Check out our calendar for other upcoming events. 

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