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.

Triggering a small wind slab will be possible at upper elevation where the new snow has blown into a slab 6 inches deep or more.  Although unlikely to bury you, any injury from an avalanche could prove life threatening if you are forced to spend the night. Carry extra layers and have a plan if you get injured or break equipment. 

Stick to slopes less than 30 degrees if you see shooting cracks or fresh avalanches.   

Problèmes avalancheux

  • Wind Slabs

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

    Small wind slabs likely formed overnight during periods of increased west wind. Weather stations stuggle to measure such low density snow,  and although most areas have 2-3 inches of new snow available for transport, some areas of the rattlesnake and upper elevation Bitterroot could have closer to 5 inches available for transport.  With this, slabs of 6 inches thick or more are possible. 

    Triggering these slabs will be possible today. While these slabs are unlikely to bury you, they could take you for a ride that results in injury or broken equipment. 

    These wind slabs should be easy to identify from their smooth rounded appearance or shooting cracks if you get too close. If you see these, avoid the problem through avoidance and stick to slopes less than 30 degrees. 

Avalanche Discussion

Across the zones yesterday, we saw the welcome sight of fresh snow. Excactly how much fell is uncertain, as SNOTEL weather sites have difficulty with such low density snow. Field observations show 1-3 inches of low density snow in the past 24 hours, but some areas may have seen closer to 5 inches.  This new snow fell on a range of interfaces, from stout crusts, to near surface facets, to surface hoar. 

The big question moving forward, is how well did the new snow preserve the surface hoar that was previously at the snow surface.  As you move around the mountains, remember where you saw surface hoar formation the past few weeks and dig in the snow to see if the surface hoar was preserved or destroyed in that area. Right now there is not enough snow above the buried surface hoar to create a slab, but once a slab forms,  we can expect a tricky and reactiive avalanche problem to develop. 

Glide cracks have opened up on isolated slopes throughout the region. Glide avalanches are highly unpredictable, and avoidance is the answer. If you see open glide cracks, do not travel underneath them. 

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

Ski and ride safe! 

Régions couvertes