Bulletin d’avalanche

Central Sierra Nevada

Sierra Avalanche Center
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Danger d’avalanche

Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré
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Périmé — ce bulletin a expiré 9 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Considerable avalanche danger exists in near treeline and above treeline areas due to wind slab avalanches.  Moderate avalanche danger exists near and below treeline due to storm slab avalanches.  Natural and human triggered avalanches are likely today.  Cautious route finding and conservative decision making are essential.

Problèmes avalancheux

  • Wind Slabs

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

    Gale force SW/W winds with additional new snow overnight will create wind slabs on NW-N-NE-E-SE-S aspects in near and above treeline areas.  Natural and human triggered wind slab avalanches will be likely today.  Small wind slabs were very reactive yesterday with wide propagation occurring as the storm moved into the area.  Large cornices exist along ridgelines and represent a significant risk to backcountry travelers.  Look for blowing snow, cornice formation, and wind pillows.  Avoid steep wind loaded terrain.   

  • Loose Dry

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

    Storm slabs will be possible on all aspects near treeline and below treeline in wind protected terrain.  These storm slabs are expected to be under 1' deep and to have poor bonding at the new snow/old snow interface.  Cold temperatures will further slow down the bonding process of this new snow and there is also the possibility that this new snow has buried a layer of surface hoar in open, wind protected, below treeline areas.  

    Look for cracking around skis.  Use small test slopes and hand pits to gather more information about the storm snow.  Avoid slopes with unstable snow.

Avalanche Discussion

Observations were made and received yesterday from Shallenberger Ridge (Donner Summit area), Carpenter Peak (Independence Lake area), Indian Valley (Ebbetts Pass area), and Echo Peak (Echo Pass area).  Avalanches were reported from Carpenter Peak and Echo Peak.  Small wind slabs were forming on Carpenter Peak with test slopes showing wind slab avalanches 2-6'' deep with wide propagation.  On Echo Peak, a cornice failure caused a wind slab to fail and run downslope over benches into lower angle terrain.  Surface hoar was reported in the Donner Summit area between 6500-7300' on N-NE aspects.

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