Bulletin d’avalanche

Tetons

Bridger-Teton Avalanche Center
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Danger d’avalanche

Tue
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Périmé — ce bulletin a expiré 4 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Human triggered avalanches on buried weak layers in the snowpack remain a concern. Carefully evaluate these weak layers on terrain that is rocky, shallow, or wind loaded before venturing onto steep slopes. Create margins of safety such as traveling one at a time to deal with the unpredictable nature of these avalanches.

Problèmes avalancheux

  • Persistent Slabs

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

    Weak layers formed during November are still buried 1-3 feet. These layers could be triggered across all aspects in the middle and upper elevations. Specific terrain in the upper elevations could have slab depths up to 4 feet, as seen in the incident that occurred Friday near Rendezvous Peak. The sensitivity of these layers has decreased over time. Terrain with shallow weak points such as rocky zones or southern aspects could have higher possibility of triggering an avalanche. In addition, terrain that continues to experience active wind loading could also increase reactivity of buried weak layers. 

Avalanche Discussion

In addition to persistent slabs, new shallow wind slabs could exist in specific terrain in the upper elevations and high end of middle elevations. Low density snow over the last several days is still available for transport. Winds have transitioned from the NW to SW over the last 48 hours averaging ~25 mph and up to 40 mph this morning.  

The persistent slab problem still haunts the snowpack. The possibility of triggering this type of avalanche in the Tetons is hard to predict due to the varying degrees of weakness between different aspects and elevations. Although the likelihood of triggering these slabs has decreased during recent dry and cold conditions, the possibility remains, particularly in steep shallow areas. Simply put, these shallow areas consist of weaker facets that are easier to trigger. This problem could be deceiving, as a slope could be mostly stable except on specific weak points.  Recent wind loading could also add stress to these weak points. The uncertainty of these persistent slabs make them a difficult problem to assess. Create large margins of safety in consequential terrain to manage this uncertainty. 

Régions couvertes