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 4 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Another day of warm temperatures will create wet snow instabilities as daytime warming occurs.  Wet loose avalanches will become possible as deep wet snow forms on steep sun exposed slopes.  A series of storms will enter our area starting tonight, with changing avalanche problems and increasing avalanche danger through the weekend. 

Problèmes avalancheux

  • Loose Wet

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

    Warm temperatures with partly sunny skies will make wet loose avalanches possible on sun exposed slopes today.  Small wet loose avalanches, roller balls, and pinwheels have been observed and reported over the last several days and are expected to continue today.  Increasing cloud cover and SW winds this afternoon could start to limit some snow surface melt.  Areas and aspects that still hold transitional snow that has not fully developed melt freeze crusts will be of concern for wet loose avalanches.  Most of these wet instabilities have been on the small side, but could have consequences if in exposed terrain or where a fall could take you into a terrain trap.

    Monitor the snow surface as you travel through terrain.  If the snow surface becomes wet and deep, it's time to change aspects or pull back into non-avalanche terrain.

Avalanche Discussion

  • Observers have reported wet loose avalanches, roller balls, and pinwheels across the forecast area. The largest wet snow instabilities have occurred on sunny E-SE-S-SW-W facing slopes, but some also occurred on NE and NW aspects. 
  • Cold unconsolidated snow is hard to find these days with some still existing on shaded steep north aspects.
  • Weak snow (facets) formed in the upper portion of the snowpack during the 38 day Jan/Feb dry spell on some wind-sheltered NW-N-NE aspects. It now exists under 6 to 12 inches of settled snow that fell during the recent storm. No avalanches have been reported on this weak layer, and most data indicates that it does not have enough load on top of it to cause avalanche problems currently.
  • Snowmelt on SE-S-SW aspects has accelerated this past week with the warm temperatures exposing bare ground in many areas and limiting on snow terrain options.

Régions couvertes