Boletín de aludes

Central Sierra Nevada

Sierra Avalanche Center
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Peligro de aludes

Fri
Alta montaña
3 · Notable
Límite del bosque
3 · Notable
Bajo el límite
2 · Moderado
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Desactualizado: este boletín caducó 2 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

A rapid increase in avalanche danger is expected this morning. The greatest avalanche danger will occur in areas that receive 6 or more inches of new snowfall today. This new snow is depositing on top of a weak old snow surface that could lead to complicated and dangerous avalanche problems.

Problemas de aludes

  • Wind Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Likely
    Tamaño
    1–2

    A period of high intensity snowfall this morning combined with strong SW winds is expected to drift and deposit new snow into locally deeper slabs of cohesive snow. These winds slabs are expected to form along the down wind side of ridgetops and in gully features, mainly in above treeline and near treeline terrain. Wind slabs may also form in more isolated areas below treeline. In some areas, especially across NW-N-NE aspects, these wind slabs could deposit on top of a weak and sugary (faceted) old snow surface. This will increase the chances of an avalanche in locations where this new snow slab over old snow weak layer combination occurs.

    Use clues such as drifting snow, cornice formation, new wind drifts, and snow surface cracking to identify areas of potentially unstable wind slab. Move around these areas with caution. Consider avoiding them in locations with about 6 or more inches of new snow.

    (12/3/2024)

    This wind slab avalanche likely failed on 11/23/24. Similar looking terrain will be prone to wind slabs avalanches for the next several days.

    Photo: Sierra Avalanche Center

  • Storm Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1–2

    Avalanches may also be triggered today in wind protected areas where 6+ inches (upper end snowfall forecast) deposit on top of old, weak sugary snow. This sugary old snow surface weak layer (facets) is most prominent on N aspects in the 7,000' to 8,000' elevation range. It has also been observed to some extent across NW-N-NE aspects, and at higher elevations throughout the forecast area on other snow covered, shaded slopes.

    Pay attention to the amount of new snow that has accumulated in wind protected areas. Look for snow surface cracking as a clue for the presence of this avalanche problem. Consider avoiding travel in avalanche terrain or below steep slopes in any area where signs of this avalanche problem exist.

Avalanche Discussion

The snowfall forecast for today is problematic, leading to uncertainty in the avalanche forecast. New snowfall amounts today could be as little as 2 inches or as much as 14 inches. Specific to today's conditions, avalanche danger is directly tied to the amount of new snowfall that actually accumulates. Pay close attention to the amount of new snow in your specific location. More new snow means a higher likelihood of avalanches. The specific condition of the old snow surface is also a major player. One portion of the forecast area could easily see no instability today, while widespread instability is observed in another portion of the forecast area.

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