Boletín de aludes

Central Sierra Nevada

Sierra Avalanche Center
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Peligro de aludes

Alta montaña
2 · Moderado
Límite del bosque
2 · Moderado
Bajo el límite
1 · Débil
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Desactualizado: este boletín caducó 6 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Fragile slabs of wind drifted snow may exist on some slopes today. In places where more snow fell, larger wind slabs will exist. In areas where less snow accumulated, wind slabs should remain small. Some wind slab avalanches may be possible today. Obstacles and  firm icy crusts below the new snow could increase the consequences of any size avalanche. Near and above treeline the avalanche danger is MODERATE.

Problemas de aludes

  • Wind Slabs

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

    Some slabs of windblown snow may have formed on the leeward NW-N-NE-E-SE aspects in the last 24 hours. These wind slabs formed on top of frozen crusts and may not have bonded well to those icy surfaces. In areas like the southern part of the forecast area and the east side of Lake Tahoe where less snow fell, most of these wind slabs should remain small.  Since more snow accumulated along the Sierra Crest in the northern part of the forecast area larger wind slabs could exist.

    Use clues like blowing snow, cornices above a slope, drifted snow, and wind created surface textures to help identity which slopes may hold fragile wind slabs.  Areas below ridgelines and cross-loaded terrain features represent likely places for the wind slabs. This information combined with how much new snow is in the area can help make informed travel plans that provide appropriate safety margins.

Avalanche Discussion

Those firm icy surfaces from yesterday still exist just below the new snow. In many areas "dust on crust" conditions will prevail today and the new snow may hide some of the uneven snow surfaces and obstacles. 

Recent Observations:

* Yesterday variable conditions ranging from firm and icy to breakable rain crust existed on Tamarack Peak (Mt. Rose area).

* Snowpit data from Silver Peak (Hwy 89 between Olympic Valley and Truckee) and Tamarack Peak found some weak snow just below the surface rain crust (near crust facets) and found the Dec 11 facets below strong supportable snow.

* In the northern 2/3rds of the forecast area, snowpit tests indicate that the Dec 11 persistent weak layer has gone dormant. Snowpit tests in some places continue to produce unstable results in the southern 1/3rd of the forecast area, especially on the eastern side of the Carson Pass and Ebbetts Pass areas where the snowpack remains shallower and weaker. Snowpit data across the forecast area (including the Carson and Ebbetts Pass areas) has shown mostly strong supportable snow above the Dec 11 facets.  

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