Bulletin d’avalanche

Central Sierra Nevada

Sierra Avalanche Center
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Danger d’avalanche

Tue
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Périmé — ce bulletin a expiré 4 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

New snow and wind will pile wind-blown snow onto slopes near and below ridges today. People could cause these slabs of wind-drifted snow to break and avalanche on some slopes. Pay attention as conditions change today, and watch out for areas where wind-blown snow exists.

Problèmes avalancheux

  • Wind Slabs

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

    As new snow and wind impact the area today, they will create new wind slabs on slopes where wind-blown snow piles up.  Wind slabs will start out small this morning, but they will grow in size as new snow accumulates today. Wind loading can increase the depth of snow by several times, and wind slabs could become large enough to cause problems for backcountry travelers during the day. Human-triggered wind slabs avalanches will become possible today. Wind slabs will most likely exist on open slopes near ridges on NW-N-NE-E-SE aspects. The largest wind slabs will exist in areas that receive the most snow. 

    Blowing snow, snowdrifts, newly formed cornices (even small ones), and other wind-created snow surface textures can all help identify where wind slabs may exist. Cracking in the new snow or recent avalanches represent sure signs that these wind slabs are unstable. If you see signs that wind slabs may exist, move around those areas with extra caution. 

Avalanche Discussion

  • Deep, wet, and unsupportable snow has been widespread for the past several days, especially on N-NE-E aspects. Wet loose avalanches have been reported on NE, ENE, E, and SE aspects. Cooler temperatures last night and today should have allowed a supportable refreeze to form on top of the remaining wet snow, and wet snow avalanches should be unlikely today. If you encounter an isolated area where the surface refreeze is not supportable, then an isolated wet loose avalanche may still be possible especially at lower elevations. 
  • In some locations, meltwater has reached the old facet layer that was buried on Feb 14 on some shaded NW-N-NE aspects. As this layer and the snow above it refreeze, avalanches on this layer should be unlikely. 
  • Snowmelt has intensified on all aspects and elevations throughout the forecast region.  Most SE-S-SW aspects have exposed bare ground in many areas limiting over snow travel options on these aspects.

Régions couvertes