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
Périmé — ce bulletin a expiré 8 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

LOW avalanche danger this morning will quickly increase to MODERATE avalanche danger all elevations as the day warms up. Loose wet avalanche activity will become possible. 

Problèmes avalancheux

  • Loose Wet

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

    Another warm sunny day means loose wet avalanche activity will quickly become possible again today once last night's weak surface refreeze melts. Sun-exposed E-SE-S-SW-W aspects hold the best potential for loose wet avalanche activity, but some loose wet instability could also form on more northerly aspects where wet surface snow may form. Wet snow instabilities could include pinwheels, rollerballs, and loose wet avalanches. Some of the loose wet avalanches could involve enough snow to injure a person.

    Wet sticky snow, boot-top-deep wet snow, active roller balls or pinwheels, and other loose wet avalanches can indicate increasing wet snow instability.  Once signs of wet snow exist, move to a colder more shaded aspect or lower angle slopes. Planning an early start and an early finish can help avoid loose wet avalanche issues. 

Avalanche Discussion

* Observations yesterday from Mt. Judah (Donner Summit area) and Ralston Peak (Echo Summit area) found firm frozen surfaces on sun-exposed aspects in the morning that softened by 10 am. 

* Corn snow conditions existed on sun-exposed slopes between 8000 ft. and 7400 ft. on SE-S aspects on Judah by 10 am. Small skier triggered roller balls started to occur on these sun-exposed aspects by 10:30 am.

* Above 8000 ft. on Ralston the snowpack had not been through quite enough melt-freeze cycles for true corn snow conditions to form. Deep wet punchy snow existed on Ralston below 7500 ft. by mid-morning. 

Régions couvertes