Bollettino valanghe

Eastside Region

Eastern Sierra Avalanche Center
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Pericolo valanghe

Thu
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
2 · Moderato
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Non aggiornato — questo bollettino è scaduto 3 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Dangerous avalanche conditions exist.  Fresh snow has added stress to our very weak snowpack. The weight of a rider may be all that is required to initiate a large and destructive avalanche. Keep in mind that any avalanche today will likely involve the full depth of the snowpack and come with elevated consequences due to the shallow and rocky nature of our snowpack.

Problemi valanghivi

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–2

    A quick-moving storm last night brought up to a foot of new snow and an inch of water weight. This is the first real stress to our fragile snowpack this season. Up to now, the lack of a cohesive slab has kept the persistent slab problem isolated. New snow has likely connected slopes, increasing the distribution and sensitivity of this problem. Shaded slopes near and above treeline will be our areas of greatest concern, particularly on terrain features where winds have added cohesion to the overlying slab. Signs of instability, such as recent avalanche activity, shooting cracks, whumphing, and collapsing in the snowpack, are signs that you may have found this problem. It may be possible to trigger a persistent slab avalanche from adjacent slopes, and avalanches may propagate long distances and  beyond terrain features that typically contain direct action avalanches such as storm or wind slabs. Keep in mind that being carried in an avalanche will have elevated consequences due to the very shallow and rocky nature of our snowpack. The easiest way to avoid this problem is to stick to lower-angle terrain without overhead hazards.

    (12/24/2023)

    This avalanche failed on buried facets and likely ran on 12/21

    Photo: Clancy Nelson

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–2

    Strong winds and fresh snowfall overnight have likely created sensitive wind slabs in leeward catchment zones near and above treeline.  You can expect the size and distribution of  wind slabs to grow throughout the day as the wind continues. Recent drifting, hollow upside-down feeling snow, and uneven snow surfaces are all clues that indicate nearby wind deposits. Be suspect of terrain features that encourage drifting, such as the leeward sides of ridgelines, alpine couloirs, gully features, and cross-loaded depressions. Keep in mind that even a relatively small wind slab avalanche breaking in the upper snowpack may be enough to step down to persistent weak layers near the ground, creating a much larger avalanche involving the full depth of the snowpack.

    (12/28/2022)

    Crown line and bed surface of size 2 human-triggered wind slab in Redcone Bowl

Avalanche Discussion

Don’t let the lure of fresh snow cloud your judgment today. There is significant overlap between areas with the most continuous coverage and areas of elevated avalanche hazard. Navigating these factors will be complex for backcountry riders.  We have a fresh load on a very weak snowpack, strong winds have been and will continue to redistribute snow throughout the day, and on the whole, the coverage remains very thin. This storm may not have been enough to initiate a large natural cycle. Rather, modest storms and incremental loading could lead to a spooky scenario for backcountry enthusiasts where human-triggered avalanches become more likely over time as new snow consolidates into a more cohesive slab and additional storms add bulk to the snowpack.

Patience remains the key ingredient.

Regioni coperte