Bulletin d’avalanche

Bitterroot

West Central Montana Avalanche Center
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Danger d’avalanche

Mon
Alpin
1 · Faible
Limite forestière
1 · Faible
Sous la limite
1 · Faible
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Périmé — ce bulletin a expiré 7 months ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Generally stable conditions exist and the risk of triggering an avalanche is low.  Even at low danger, small avalanches in isolated or extreme terrain are possible.

Take the time to assess the slope you plan to ski or ride for wet unsupportable snow, or dig and look for a slab with weak snow beneath it. If you find these, avoid avalanches by moving elsewhere or sticking to low angle slopes under 30 degrees. 

Problèmes avalancheux

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–1.5

    With arctic air to the east over eastern Montana, we are seeing light  east winds and temperatures falling into the low 30s. Overnight clear skies and cool temperatures will freeze yesterday's wet snow into a supportable crust. With it being mid January, sun angles are still low, and the sun doesn't have the warming strength it does in the spring. As a result, it will take time for the surface crust to break down and we don't anticipate a widespread wet snow avalanche cycle today. 

    There will be pockets of terrain that did not get a solid re freeze or that are seeing more direct sun where wet snow avalanches will be possible, especially around rock bands or in extreme terrain. If you find yourself sinking into wet or unsupportable snow, it is time to move to non solar slopes to find dry snow and avoid avalanches. Any wet snow avalanches are likely to be small, but could run far or be destructive in extreme terrain like couloirs or chutes.

Avalanche Discussion

When will it snow again? By the end of next week the current high pressure system looks like it will break down and bring a shift with the potential for new snow. In the meantime, the current pattern persists and today's avalanche forecast reads similar to the previous three. 

You should notice that we have removed the persistent slab as a problem. We have not seen an avalanche on these layers in weeks, and triggering a larger persistent slab avalanche is unlikely. Having said that, it is a large forecast zone and isolated terrain at upper elevation still has poor snowpack structure with faceted snow beneath a crust or buried facets 1-1.5 feet deep.  You are unlikely to see cracking or collapsing before triggering an avalanche on these layers. To identify the problem, dig in the snow and look for a slab (strong snow) above the facets (weak or sugary snow). If you find this, the best way to avoid the avalanche problem is with slope angle. Slopes under 30 degrees are very unlikely to avalanche on these layers.

We are seeing near surface faceting and surface hoar growth at the snowpack surface during this high pressure event. When it does snow later this week, we will likely have a new persistent slab layer to worry about and the problem will likely re appear.

Low danger is not no danger. Even at low avalanche danger, you need to be on the lookout for red flags or signs of instability and take the time to assess the slope you plan to ski or ride. Always use safe travel practices like riding one at a time and being aware where other riders are. Even a small avalanche can have serious consequences if you are stepping out into extreme terrain like couloirs or large exposed faces. 

With the sun and warm temperatures, we may see natural cornice failures and small slab avalanches beneath them. Do not spend unnecessary time underneath cornices during the heat of the day. 

Glide cracks have opened up on isolated slopes throughout the region. Glide avalanches are very difficult to forecast or understand due to their unpredictability. The time between a crack opening up and the avalanche failing can vary from minutes to months. Avoidance is the answer. If you see open glide cracks, do not travel underneath them. 

Avalanche education is a lifelong journey built on developing sound judgment, gaining experience, and applying repeatable decision-making systems in the backcountry. Our American Avalanche Association (A3) recognized Level 1, Rescue, and Level 2 courses are offered throughout the winter and help you travel smarter in avalanche terrain. Explore current courses and registration on the Education page. 

Thank you for all of the great observations recently. They help us create better forecasts, and we truly appreciate them. Please keep submitting them! 

Ski and ride safe!

Régions couvertes