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

As the snow surface melts this morning, the potential for wet loose avalanches will increase on steep slopes as the day progresses. It's time to exit avalanche terrain once the snow surface looses supportability and deeper wet snow is encountered.

Problèmes avalancheux

  • Loose Wet

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

    Air temperatures remained above freezing last night in nearly all locations above the mountain valley floors. Many locations on the peaks did not get any colder than the low 40s overnight. With clear skies last night, the top couple inches of the snow surface is expected to have refrozen as a product of radiational cooling. This thin refreeze will be strongest on open slopes. Areas under forest canopy will have experienced little to no refreeze last night.

    The refrozen snow surface is expected to melt quickly today due to well above freezing air temperature at sunrise that warm into the mid 50s to low 60s as the morning progresses. The vast majority of wet loose avalanches that occur today will be triggered by backcountry travelers venturing into steep terrain. Cornice collapses could result in some isolated natural wet loose avalanches.

    For travel in avalanche terrain today, start early and end early. Monitor the changing snow surface as melt progresses. Once the surface crust from last night is gone, wet loose avalanches can occur. When the snow becomes wet and unsupportable, or you can sink boot top deep into wet snow, it's time to exit avalanche terrain and opt for lower angle slopes.

    (4/9/2025)

    Signs of surface wet snow instability, past and present. Mt. Judah, Donner Summit area, CA

    Photo: Sierra Avalanche Center

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