Bulletin d’avalanche

Central Sierra Nevada

Sierra Avalanche Center
Voir sur la carte

Danger d’avalanche

Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
3 · Marqué
Périmé — ce bulletin a expiré 10 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Human triggered wind slab and storm avalanches are likely today. Natural avalanches are possible. CONSIDERABLE danger exists at all elevations. Some large and destructive avalanches could occur. Dangerous avalanche conditions exist. Carefully evaluate the snowpack and the terrain before committing to any slopes. Use this information to make conservative and cautious decisions and plan safe routes of travel that avoid avalanche problems. As another strong winter storm impacts the region tonight through Monday morning, the avalanche danger will increase.

Problèmes avalancheux

  • Wind Slabs

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

    Strong S and SW winds and additional snow have added to the fragile wind slabs that already exist on wind-loaded W-NW-N-NE-E-SE aspects. While the largest and most sensitive wind slabs will exist in near and above treeline terrain, some wind slabs may also exist on wind loaded slopes in below treeline terrain. As more snow and wind impact the region today and in the next 48 hours, these wind slabs will grow larger and more widespread. Human triggered wind slab avalanches are likely today and natural wind slab avalanches are possible. Some large and destructive wind slab avalanches could occur in areas with heavy wind loading. 

    Use blowing snow, cornices, wind drifted snow, and other wind created features and textures to identify where wind slabs may exist and avoid those areas. 

  • Loose Dry

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

    Changing conditions during the storm have allowed weak layers to form within the storm snow. Human triggered storm slab avalanches will be likely today and some natural storm slab avalanches may remain possible. Any steep slopes with new snow on them hold the potential for storm slab avalanches. 

    Clues like cracking, collapsing, and whumphing can help identify where storm slabs may exist as can digging into the snowpack with your hands or probing with a pole to look for layers in the storm snow. Use these clues to avoid steep terrain where storm slabs may exist. Storm slabs can exist on tree covered slopes in the openings between trees and may connect across some of these open spaces. 

Avalanche Discussion

Widespread human-triggered wind slab avalanches occurred on Jakes Peak, Andesite Peak, and Incline Lake Peak yesterday. These avalanches had crowns ranging from 1 to 2.5 ft. They were triggered by ski cuts and small cornice pieces dropped onto the slopes. Some of them were triggered remotely. These avalanches failed within the storm snow. In addition to these wind slabs shooting cracks and unstable test results were noted on Andesite Peak in below treeline sheltered terrain. 

Régions couvertes