Bulletin d’avalanche

Central Sierra Nevada

Sierra Avalanche Center
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Danger d’avalanche

Fri
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
2 · Modéré
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Périmé — ce bulletin a expiré last year. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Areas of unstable wet snow remain possible today with the potential for wet loose avalanches in areas that received little to no snow surface refreeze last night. Consider moving to lower-angle slopes if you encounter a few inches or more of wet snow on the surface. Some small, isolated slabs of wind drifted snow might form late today near ridgetops in the unlikely event that a couple inches or more of new snow accumulates today.

Problèmes avalancheux

  • Loose Wet

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

    Mostly cloudy, windy conditions last night and a warm air mass already in place kept air temperatures above freezing last night at and below 8,500'. Thicker cloud cover typically limits overnight refreeze. Anticipate that last night, a weak to decent refreeze occurred above 9,000', while a weak to nonexistent refreeze occurred below 8,500'.

    Wind and cloud cover today are expected to reduce the amount of snow surface melt. The most problematic areas today are expected near and below 8,500' where poor refreeze conditions and the potential for some light rain on snow today keep the wet loose avalanche problem ongoing.

    Signs of wet snow instability include sinking boot-top deep into wet snow, as well as triggering roller balls and pinwheels. These signs indicate that you could trigger larger, wet loose avalanches. It's time to exit avalanche terrain and move onto lower angle slopes if signs of unstable wet snow are encountered.

    Cornice collapses may remain a problem today in areas that experienced little to no refreeze last night. If your route takes you along a corniced ridge, keep exposed rocks or trees between you and the cornice edge. If you choose to travel on a slope below a large cornice, spend as little time as possible doing so.

    (3/25/2025) Cornice fall triggered a large wet loose avalanche on a NE aspect. Donner Peak, Donner Summit area, CA

  • Wind Slabs

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

    SW winds are gale force today, but new snow amounts forecast for today are rather meager. In the event that a couple of inches or more of new snow manage to accumulate today, some small, isolated slabs of wind drifted snow might form near ridgetop areas. Wet snow and melt freeze crust on windward aspects will keep any problematic amounts of old snow from blowing around. Any new slab formation will require new snowfall.

    Any new wind slabs that form by late today are not expected to present much of a hazard to backcountry travelers outside extreme terrain. Depending on the amount of new snowfall that accumulates tonight and tomorrow, this avalanche problem could slowly develop into a bigger issue.

Régions couvertes