Bollettino valanghe

Central Sierra Nevada

Sierra Avalanche Center
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Pericolo valanghe

Sun
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
3 · Marcato
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In sintesi

Today's intense solar heating and high sun angles are expected to create avalanche problems associated with rapid warming across all aspects today. Avalanche problems will become increasingly problematic as the day progresses. The best bet is to time travel in avalanche terrain during the morning hours and to consider avoiding avalanche terrain during the afternoon hours.

Problemi valanghivi

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–2.5

    It's April and the sun angles are now high enough to create wet snow on all aspects. Rapid warming of the 2 to 6 inches of new snow from the past 24 hours is expected to lead to wet loose avalanches occurring on all aspects today. Long open slopes with sustained slope angles will have the potential to create the largest wet loose avalanches as more snow becomes entrained following the initial point release.

    Rollerballs and pinwheels are indications that this avalanche problem is present. Consider moving to slopes less steep than about 35 degrees in slope angle to reduce the risk of becoming caught in a wet loose avalanche.

    (4/7/2023)

    A shallow wet loose avalanche triggered intentionally in an area where roller balls were present. It did not take much warming yesterday to create this instability. NE aspect near 7,800' on Hidden Peak, West Shore Tahoe area, CA.

    Photo: SAC

  • Cornices

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1.5–2.5

    A natural cornice fall cycle is possible starting today, increasing in likelihood tomorrow through Monday. Some of the cornices out there near treeline and above treeline on N-NE-E aspects range in size from very large to massive. Falling blocks of very dense snow will have some destructive potential.

    The exact moment that a cornice fall will occur is nearly impossible to predict and is often larger than expected. Nearly everyone involved in a cornice fall incident while on a ridgetop is caught by surprise when the cornice breaks off much further back from the edge than expected. Stay well back from cornice areas on ridgetops and consider avoiding travel on slopes underneath cornices.

    (3/31/2023)

    It won't take much for some of these cornices to collapse. Ward Canyon, CA

    Photo: Public

  • Wind Slabs

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

    Rapid warming today may increase the instability of wind slabs that formed yesterday in locations where wind drifted snow was deposited near ridgetops and into gully features. Cornice fall may also trigger wind slab avalanches today.

    Use clues such as cornices, wind drifts, snow surface texture, recent avalanches, and snow surface cracking to identify areas where problematic wind slabs may exist. Move cautiously around these areas and consider avoiding slopes below cornice features.

Regioni coperte