Bulletin d’avalanche

Salt River and Wyoming Ranges

Bridger-Teton Avalanche Center
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Danger d’avalanche

Sun
Alpin
3 · Marqué
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

Recent snow and wind have formed slabs 1 - 3 feet deep. Human-triggered avalanches are likely on steep terrain in the upper elevations.  The possibility of triggering a larger avalanche on buried weak layers 3 - 4 feet deep remains in terrain above 8500'. Avalanches are unlikely in lower elevations except for isolated pockets of very steep terrain.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–2

    Over the past 48 hours, 1 - 1.5 feet of new snow and strong southwest winds have formed slabs up to 1 - 3 feet thick in the middle and upper elevations on leeward aspects. Yesterday, numerous natural and human-triggered wind slabs were reported in the adjacent Teton zone. Expect these slabs to be larger, and sensitive to human triggers today. Recent high wind speeds have caused slabs to form further down and across slopes than normal. Carefully evaluate terrain where wind slabs typically form - ridgelines, cross-loaded gullies, and leeward slopes. The formation of drifts, fresh cornices, or blowing snow will help you identify fresh slabs. Watch for obvious signs of instability such as shooting cracks, collapsing, and recent avalanches. Seeking lower-angle or wind-sheltered terrain will help reduce your risk.

    (2/7/2025)

    A D1 windslab NE, ~8500’ from yesterday in the Teton Zone. Note the drift formation and thicker crown in the center. 

  • Persistent Slabs

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

     Triggering a very large avalanche big enough to bury you is possible on steep, rocky, convex, or wind-loaded slopes over 35°. The 3-4 feet of snow that fell this past week sits on a weak layer that formed 1/31. Managing this problem will be difficult because signs of instability - such as collapsing, cracking, or recent avalanches - may not be present. Multiple tracks on a slope are not necessarily an indication that it is safe – it might take one more rider to find the trigger point. Choose conservative and lower-angle terrain to manage this high-consequence avalanche problem. 

    Weak snow, buried 3-6 feet deep, is under stress from recent loading in shallow snowpack areas like the Wyoming and Gros Ventre Range. Though deep avalanches remain unlikely, keep these layers on your radar if traveling in shallow parts of the forecast zone.

     

    (2/3/2025)

    A large avalanche triggered from below in the Salt and Wyoming Ranges.

    Photo: Ray Landry

Avalanche Discussion

Recent winds and new snow have created wind slab avalanches across the zone. There was a lot of activity reported in the Teton zone, with a number of both natural and human-triggered avalanches reported. Peak sensitivity likely occurred yesterday during the initial loading, but an additional 4 - 10 inches of snow in the past 24 hours will keep the avalanche hazard elevated today. Particularly strong and consistent winds will have also distributed snow into some unexpected areas. The Salt Range - particularly to the south - received up to 10" of snow while the Wyoming Range received 4" of snow. Due to the varying snow totals - slab depths through the range may vary significantly. The general rule of thumb - the more snow that fell, the larger the avalanche. 

The snowpack has gone through a lot of rapid change since January 31st, causing unstable snow in the top portion of the snowpack. Before the recent storms, cold and dry conditions formed widespread weak layers of facets across many aspects and elevations. These weak layers are now buried by dense slabs and capable of producing destructive avalanches. Over 3” of snow water equivalent (weight of the snow) fell onto this weak interface – that’s a lot of weight, and the snowpack is still adjusting.

Please continue to send in your observations, thanks!

Régions couvertes