Bulletin d’avalanche

Central Sierra Nevada

Sierra Avalanche Center
Voir sur la carte

Danger d’avalanche

Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré
Open full map
Périmé — ce bulletin a expiré 7 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Avalanche danger is increasing today. CONSIDERABLE avalanche danger is expected to develop this afternoon in above treeline and near treeline areas due to wind drifted snow forming into wind slabs. MODERATE avalanche danger is expected this afternoon below treeline due to the possibility of new snow forming into storm slabs.

Problèmes avalancheux

  • Wind Slabs

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

    Once snowfall intensifies today, wind slabs will grow in size and distribution. Areas of wind drifted snow are expected to form unstable wind slabs this afternoon in near treeline and above treeline terrain, mainly on NW-N-NE-E-SE aspects. The expected avalanche size is D2.

    Use clues such as blowing snow and signs of past blowing snow including cornices, wind pillows, and scouring vs deposition patterns along ridgelines to identify the most likely location of wind slabs and make a plan to avoid them.

  • Loose Dry

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

    New storm slabs are possible as an avalanche concern by sundown, becoming deeper and more widespread as new snow continues to accumulate during the evening hours in wind protected areas below treeline on all aspects. The expected avalanche size is D1 to D2.

    Areas of snow surface cracking in wind protected areas are a sign of storm slab instability. Using lower angle slopes and avoiding steeper slopes above is a way to manage this problem. If storm slab instability does not form, expect loose dry avalanche problems (sluff) instead.

Avalanche Discussion

Some loose wet avalanches were noted yesterday near Mt. Lola (Independence Lake area) on steep N-NE aspect complex terrain at 8,000'. A few small wind slab avalanches that were a day or two old were also noted in this same location.

Snowpit data continues to show good bonding of the layers in the bottom and middle portions of the snowpack. The snowpack continues to gain complexity with various rain crusts. No problematic weak layer formation (faceting) around these crusts has been reported.

Régions couvertes