Bulletin d’avalanche

Snake River Range

Bridger-Teton Avalanche Center
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Danger d’avalanche

Sat
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Périmé — ce bulletin a expiré 2 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Triggering a large avalanche on weak snow buried 2-4 feet deep is possible. These avalanches are most likely on very steep, rocky, wind-affected terrain. Avalanches are unlikely at lower elevations. 

Problèmes avalancheux

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1.5–2.5

    Although triggering an avalanche involving these layers has become less likely, it can still occur, especially above 8000 feet in terrain that is connected to very steep (>35°) slopes. 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 one of these avalanches. 

    Larger triggers in the form of groups, snowmobiles, or falling cornices will increase the odds of impacting these weak layers. Snowpack evaluation and safe travel practices remain the best methods to avoid triggering an avalanche involving the old snow layers. 

    (1/16/2025)

    An example of a steeper, wind-affected slope where trigger points for a hard slab avalanche could be close to the surface.

    Photo: Bridger-Teton Avalanche Center

Avalanche Discussion

The Snake River Range is expected to receive 1-3" of new snow today.  Northwest winds are expected to be strongest in the morning before the snow begins to fall this afternoon. Stay alert for isolated pockets of wind-drifted snow that may develop later today at high elevations. Keep an eye out for signs of instability such as cracking, and the formation of small drifts. Move to terrain sheltered from the wind if you're finding signs of instability developing.

The spatial distribution of 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 an avalanche. 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 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')

Régions couvertes