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
3 · Marqué
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Périmé — ce bulletin a expiré 7 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

CONSIDERABLE avalanche danger will exist at all elevations due to wind slab, storm slab, and loose wet avalanche problems.  A storm will bring heavy snow to our forecast area today and tonight.  Human triggered avalanches are likely with natural triggered avalanches possible.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    2

    Wind slab avalanches will be likely today on NW-N-NE-E-SE aspects in near and above treeline terrain.  Gale force SW winds will transport new snow and create large wind slabs today in wind exposed areas.  Wind slab development may also be possible on other aspects or in below treeline areas with ridge wind gusts near 100mph.

    Avoid steep wind loaded terrain and areas near or below wind loaded slopes and cornices.  Widespread blowing snow is expected in all but the most protected below treeline areas.   

  • Loose Dry

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

    Storm slab avalanches will be likely on all aspects in near and below treeline terrain.  1 to 2 feet of new snow is forecasted to fall by tonight or early Thursday morning.  Storm slab weakness could occur within the new storm snow or at the old snow/new snow interface.  Storm slabs could have wet slab characteristics as daytime warming and the potential for rising snow levels occurs today.

    Look for cohesion of the new storm slabs or heavier snow over lighter snow.  Cracking or collapsing will indicate potential weakness within the new storm slab.  Utilize lower angle terrain to help limit exposure to steeper slopes.

  • Loose Wet

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

    As daytime warming occurs today along with the potential for rising snow levels, loose wet avalanches will become likely on all aspects.  Depending on warming, most loose wet avalanche activity should be limited to areas below 7500'.  Loose wet avalanches could involve the current storm snow and also the recent storm snow that sits on top of an old surface crust.  Roller balls and pinwheels will be an indicator that the surface snow is decreasing in strength and larger loose wet avalanches could occur.   

      

Avalanche Discussion

*  More sun was seen on Hidden Peak (West Shore area) with a poor overnight refreeze of the snow surface.  Small loose wet avalanches (D1) involving the top 2-3'' of snow were easy to trigger on steeper slopes between 8400-6800' range.

*  Warm conditions existed on Silver Peak (Pole Creek area) with 2-3'' of new snow above 8000'.  Small roller balls occurred while down skiing with light rain below 6800'. 

*  Observations from Trimmer Peak (Luther Pass area) showed a variety of snow surfaces with little signs of instabilities.

Régions couvertes