Bulletin d’avalanche

Central Sierra Nevada

Sierra Avalanche Center
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Danger d’avalanche

Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Périmé — ce bulletin a expiré 7 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

MODERATE avalanche danger lingers above 9,000' in above treeline and near treeline terrain due to shallow slabs of wind drifted snow (wind slabs). Anticipate a travel hazard today with rain crust on all aspects up to about 9,000' making long sliding falls possible. LOW avalanche danger exists for areas below 9,000' and for below treeline terrain.

Problèmes avalancheux

  • Wind Slabs

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

    For areas above 9,000', shallow wind slabs may linger in near treeline and above treeline terrain on all aspects. Recent strong to gale force ridgetop winds have shifted between SW to W and NE to E over the past several days. Light to moderate amounts of blowing and drifting snow has been observed in recent days with about an inch of new snow above the rain/snow line yesterday. A mix of hard slab and soft slab conditions exist. Any shallow wind slab avalanches that occur today are expected to be D1 in size. Evaluate other terrain features such as cliffs below, rocks, trees, and terrain traps that would magnify the consequences of an otherwise small avalanche.

    Other things to consider: 1) Newly formed rain crust below about 9,000' may present a travel hazard today. Firm conditions could make long sliding falls possible or breakable crust may be encountered. 2) It is unlikely but not impossible that warming today may be sufficient to melt the rain crust on some SE-S-SW aspects, allowing for roller balls and small loose wet avalanches.

Avalanche Discussion

* An unforecast rain event occurred yesterday across the forecast area with 0.1 to 0.15 inches of rain up to about 9,000'. Around an inch of snow fell above the rain/snow line.

* The top 1 to 2 inches of the snowpack was wetted by yesterday's rain below about 9,000' with roller balls reported below treeline.

* New rain crust was observed forming on the surface yesterday afternoon as snow surface refreeze occurred. Expect firm to breakable crust conditions on all aspects today up to about 9,000'.

* Thin wind slab was reported yesterday beneath cornice on Incline Peak at 9,400' on a NE aspect.

Régions couvertes