Bulletin d’avalanche

Eastside Region

Eastern Sierra Avalanche Center
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Danger d’avalanche

Mon
Alpin
4 · Fort
Limite forestière
4 · Fort
Sous la limite
4 · Fort
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Périmé — ce bulletin a expiré 3 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Heavy snowfall and wind loading at increasing rates will result in widespread avalanche activity. Avalanche danger will continue to rise overnight. Avoid being around or underneath steep terrain through Monday.

Problèmes avalancheux

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Certain
    Taille
    1–3

     Storm instabilities, both slabs and sluffs will grow in size, becoming more sensitive as the day progresses. Large avalanches failing within the new snow will be possible in all areas. South winds will drift snow onto leeward slopes, resulting in larger and more frequent avalanches. Avoid being on or under steep terrain over 30° today and be cognizant of your exposure to terrain features that increase the consequences of avalanches. This includes road cuts, gully features, cliff bands, and mid-slope depressions. As significant snow accumulates in mountain communities be aware of overhead hazards from roofs and short steep slopes above confined areas.

    Photo: Steve Mace

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Very Likely
    Taille
    2–3.5

    In areas that have held snow since December, persistent weak layers at the base of the snowpack will not be able to withstand the intensity of today's storm. Hard slabs failing on these layers will involve the full depth and weight of the snowpack. Persistent slab avalanches can propagate long distances, connecting terrain features that typically contain surface instabilities such as storm or wind slabs making for larger and more destructive avalanches that are difficult to avoid. As the storm progresses and the tracks and runouts of avalanche paths fill with loose snow avalanches may begin to reach their maximum runouts and impact valley floors.

    (2/3/2024)

    A very large persistent slab avalanche on Mt. Laurel. This released naturally with the last 48 hours.

    Photo: Everett Phillips

Avalanche Discussion

Recent Avalanches: Incremental loading over the past 48 hours extended the natural avalanche cycle that began on 1/31/24. As skies cleared yesterday multiple very large natural persistent slab avalanches were reported as having failed due to wind loading overnight between 1/2/24 and 1/3/24. Over the past 24 hours, multiple human-triggered avalanches were reported involving recently deposited wind slabs. These avalanches occurred on multiple aspects from SE to N at all elevations.

Snowpack Discussion: On slopes that held snow in December a layer of depth hoar and basal facets is buried between 3 and 5 feet below the snow surface under a strong mid-pack slab. Lower than average snow depth had previously contained impacts from these avalanches involving these layers to upper elevations. Once 2 to 3 ft. of loose new snow accumulates in the tracks and runouts on northerly avalanche paths persistent slab avalanches may begin to threaten the runouts and flat terrain on valley floors.

Incoming storm: Over the next 48 hours, 40" to 60" of snow is expected in the Eastern Sierra.  The storm will impact the entire forecast area, with snow accumulation down to valley floors. Terrain that was previously inaccessible due to low snow will likely become ridable for the first time this season. At the same time, avalanche paths in areas that previously had exposed ground will accumulate enough snow to produce avalanches. 

Heavy snowfall will cause travel impacts in mountain communities and on highways. Park responsibly so as not to block snow removal crews working to restore access for residents and emergency services. Travel in avalanche terrain is not recommended.

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