Boletín de aludes

Snake River Range

Bridger-Teton Avalanche Center
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Peligro de aludes

Thu
Alta montaña
3 · Notable
Límite del bosque
3 · Notable
Bajo el límite
2 · Moderado
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Desactualizado: este boletín caducó 2 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Remotely triggering a very large avalanche is possible in some terrain. While not a widespread problem, the consequences of triggering an avalanche that fails on the ground are severe. You can reduce your risk and avoid this problem by avoiding slopes over 35 degrees, particularly those which have been wind effected or contain a shallow snowpack.

Two days ago, four riders were buried, two fully, when they triggered a very large and very wide avalanche from the bottom of a slope. Luckily, no one was killed though one rider was buried over four feet deep.

 

 

Problemas de aludes

  • Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1.5–3

    Weaker snow layers now buried 3-4+ feet deep have not gone away, but they've become less reactive to the weight of a skier or rider. Due to their depth, they've also become difficult to trigger with your weight in most areas. New snow this afternoon may further stress these layers.

    Where: Terrain features and areas with a shallower snowpack. Very steep slopes over 35 degrees primarily on the aspects shown.

    What: 2-4' thick slabs over faceted snow and depth hoar. Avalanches have been triggered remotely as recently as yesterday. These avalanches could bring down the entire seasons snowpack on you. 

    You can avoid trouble by steering clear of slopes over 35 degrees with a shallower snowpack. 

    Yesterday, a rider remotely triggered an avalanche in Ditch Creek in the Togwotee forecast zone. While relatively small, the avalanche failed at the ground and is a good example of this persistent problem type.

    One avalanche outside of the boundary at Grand Targhee Resort was triggered by a skier 3 days ago on this deeper weak layer. Fortunately, this person walked away unharmed. 

     

    (12/31/2024)

    Large remotely triggered avalanche that failed on persistent weak layers. The avalanche propagetd out of view to the left and right.

     

Avalanche Discussion

We visited the site of a very large avalanche yesterday which was triggered at the bottom of the slope. The slide propagated approximately 1500' and wrapped around numerous terrain features. There were no clear signs of unstable snow on Monday when the avalanche was triggered or yesterday when we visited though in good light you could see signs of old wind drifts and wind stripped slopes.  Reports of collapsing and whoompfing continue to be reported in other areas but not here. The only sure way to find this problematic snow structure is to dig. New snow today may add load and stress to this layer but colder temperatures and limited snowfall make it unlikely that one of these avalanches will fail without a human trigger. 

You can watch a video summary of the recent accident here and read the details here. While these persistent weak layers are creating a human triggered avalanche problem currently, the surprising nature of these potentially very large avalanches earn the elevated danger rating today.

Thank you to all who have contributed observations during this cycle. This allows everyone to gain a better and more complete understanding of conditions. You can submit observations and photos HERE or text 307-264-3050

 

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