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
2 · Modéré
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Périmé — ce bulletin a expiré 6 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Above freezing overnight temperatures along with mostly clear skies will provide a weak refreeze of the snow surface.  Rapid warming starting early this morning will make loose wet avalanches and cornice fall avalanche problems for today.  MODERATE avalanche danger will exist at all elevations.

Problèmes avalancheux

  • Loose Wet

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

    Above freezing overnight temperatures with mostly clear skies should have allowed radiational cooling to provide a weak refreeze of the snow surface.  Rapid warming will quickly melt through this snow surface crust and weaken bonds starting early this morning.  E-SE-S aspects will melt the quickest, followed by varied rates on SW-W-NW-N-NE aspects.  Loose wet avalanches will become possible as the snow becomes wet and deep. 

    Avoid avalanche terrain once it becomes unsupportable.  Monitor snow surface conditions while in the backcountry .  Once it becomes wet and deep, it's time to change aspects or call it a day. 

  • Glide Cracks

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

    A weak overnight refreeze with rapid warming today could allow for additional cornice fall to occur.  Large cornices can be destructive by themselves and could additionally cause loose wet or wet slab avalanches to occur on the slopes below. 

    Avoid areas below large cornices.  Stay well back from the edge of cornices along ridgelines and avoid any large cracks that are developing on the backside of cornices.

       Photo:  Small cornice fall along Mt. Judah, Donner Summit area.  

Avalanche Discussion

Observations were received yesterday from Forestdale (Carson Pass area).  A better than expected snow surface refreeze occurred with supportable riding conditions until 1:30pm.  Large cornices overhang many slopes throughout this terrain.

Observations from Mt. Judah (Donner Summit area) showed a short window for supportable conditions on sun exposed slopes.  By 9:30am, E aspects below 7600' were deep, wet, and unsupportable.  Many loose wet avalanches and cornice fall have occurred in this area over the last few days.

Régions couvertes