Bollettino valanghe

Snake River Range

Bridger-Teton Avalanche Center
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Pericolo valanghe

Tue
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 2 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Triggering a large avalanche that fails on weak snow buried 2-4 feet deep is unlikely, but carries high consequences. These avalanches are most likely in very steep, rocky, and wind-affected terrain. Evaluate complex terrain features carefully and practice safe travel habits in avalanche terrain.

Problemi valanghivi

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely
    Dimensione
    1.5–2.5

    Weak layers of snow are buried 2-4 feet deep in the Snake River range. Triggering a large hard slab avalanche at these depths has become unlikely, but is not impossible. A very large natural avalanche involving these layers occurred on January 7th and is a good reminder of weak snow lurking below. Triggering a persistent slab avalanche is most likely in very steep, north facing terrain where the snowpack is thinnest. Thin spots (trigger points) include wind-scoured slopes, cliff bands, and rocky areas. Obvious signs of instability, such as collapsing and cracking, may not be present prior to triggering a large avalanche.

    Larger triggers such as groups, snowmobiles, or falling cornices, will increase the odds of impacting these weak layers. This avalanche problem is currently a low likelihood/high consequence scenario. Choosing terrain that reduces your exposure and remaining vigilant when traveling in avalanche terrain is important given this setup.

    (1/16/2025)

    An example of complex terrain in the Snake. Very steep, wind affected slopes where trigger points for a hard slab avalanche could be close to the surface.

    Photo: Bridger-Teton Avalanche Center

Avalanche Discussion

The snowpack in the Snake River range is relatively deep, but weak snow can still be found below the surface. The early season brought minimal amounts of snow and cold temperatures. This helped to form weak layers of snow close to the ground. Beginning in mid December, storms deposited snow and created hard slabs on top of this weak snow. These slabs now range between 2-4 feet in depth. Snowfall has gradually tapered off since January 11th. The snowpack has adjusted to the loading and stability has increased as a result. While it is possible to travel over a significant amount of steep terrain in the Snake without incident, it is important to understand that persistent slab problems are tricky and stick around longer than we would like. The weak layers buried near the ground are trending towards dormancy, but we are not quite there yet. For the time being, it is wise to fight complacency and not let your guard down in avalanche terrain.

Want to learn more about how triggering a persistent slab avalanche from a thin spot works? Check out this sweet video made by a seasoned avalanche professional.

Also, please consider submitting an observation HERE. Observations allow everyone to gain a better and more complete understanding of conditions. Thanks!

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