Bollettino valanghe

Snake River Range

Bridger-Teton Avalanche Center
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Pericolo valanghe

Sun
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 failing on weak layers buried 2-4 feet deep is unlikely but carries high consequences. These avalanches are most likely on very steep, rocky, wind-affected terrain. Continue to evaluate the snowpack and use safe travel practices in avalanche terrain.

Problemi valanghivi

  • Persistent Slabs

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

    Although triggering an avalanche involving buried weak snow layers has become unlikely, it can still occur, especially above 8000 feet in terrain connected to very steep (>35°) slopes. This problem type can appear inactive - the last reported avalanche in this zone was 11 days ago on January 7th in Waterfall Canyon - but should remain a concern to backcountry users due to its difficult-to-predict nature. You're most likely to trigger a large hard slab avalanche 2-4 feet deep on the north half of the compass - where snowpack depth is variable. These avalanches are easiest to trigger in spots where the snowpack is thin. Signs of a thin snowpack include wind-scoured snow near ridges, cliff bands, and rocks sticking out of the snow. Signs of instability, such as snowpack collapsing and cracking, probably won't be present before triggering a large persistent slab 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 but high-consequence scenario. Snowpack evaluation and safe travel practices remain the best methods for avoiding triggering an avalanche involving the old snow layers.

    (1/7/2025)

    Large persistent slab avalanche on a steep, rocky, north-facing slope.

Avalanche Discussion

Yesterday, the Snake River Range received up to 3" of new snow with light winds from the NW. It’s unlikely these conditions have created a fresh avalanche problem, but exceptions may be found. Stay alert for isolated pockets of wind-drifted snow that may have developed at high elevations. Keep an eye out for signs of instability such as cracking, and the formation of small drifts. These avalanches will most likely be small but could carry high consequences in complex terrain. Move to terrain sheltered from the wind if you notice signs of instability. 

The spatial distribution of overall snow depth varies across this forecast zone. This is important to acknowledge as areas with a shallower snowpack generally have a weaker snowpack. A shallower snowpack also means that the overlying slab above the persistent weak layers is thinner and easier to trigger. Therefore, you should use more conservative terrain choices anywhere where the snowpack is shallower. Persistent slab avalanches are difficult to predict. We have been seeing positive trends of increased stability in the buried weak layers during our travels but we are not out of the weeds woods quite yet. Be patient, there will be plenty of days later in the season where stepping out into more complex terrain will be safer with less severe consequences.

Snake River Range:  

  • Total Snow Depth- 79" (Baird Snow, 8900')
  • Total Snow Depth - 31" (Snake River Canyon, 5,698')

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