Bollettino valanghe

Central Sierra Nevada

Sierra Avalanche Center
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Pericolo valanghe

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

In sintesi

Unstable, wet snow will form quickly today on many slopes in response to daytime warming. Areas of overhanging snow (cornices) along ridgetops may continue to collapse. Consider moving to lower-angle slopes once a few inches of wet snow forms on the surface. Consider avoiding slopes below large cornices.

Problemi valanghivi

  • Loose Wet

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

    Three nights in a row of above freezing air temperatures and poor snow surface refreeze conditions have occurred. The potential for wet loose avalanches will develop quickly again today. Increasing winds may slightly slow the snow surface melt on some slopes today, but wet snow instability is still expected.

    Wet loose avalanches have been observed on all aspects over the last few days. The incoming solar radiation is strong this time of year and the sun angle is high, making for wet snow on all aspects and at all elevations. Wet loose avalanches could easily entrain enough snow to knock a person over or push them into a terrain trap that magnifies the consequences of an otherwise small avalanche. On long, steep slopes, wet loose avalanches gather more snow as they slide downhill, and could become large enough to bury or injure a person.

    Anyplace that a frozen, supportable snow surface exists first thing this morning will be short lived. Surface crust will melt, and snow conditions will get wet and mushy very quickly again today. Signs of developing wet snow instability include sinking boot-top deep into wet snow, as well as triggering roller balls and pinwheels. These signs indicate that you could trigger larger, wet loose avalanches. It's time to exit avalanche terrain and move onto lower angle slopes once the snow surface becomes wet and unsupportable.

    (3/25/2025) Recent wet loose avalanches on the E aspect of Elephant's Back. It appears that cornice fall triggered the avalanche on the right. Carson Pass area, CA

    Photo: Kelly Chang

  • Cornices

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

    The large overhanging cornices that exist along many ridgelines have undergone several warm days and nights, and have started to collapse. Additional cornice collapses may occur today. Significant uncertainty exists as to exactly when a specific cornice will fail. Cornice collapses can occur naturally, or a person traveling a ridgetop can trigger a cornice collapse. This can result in taking a long fall and/or get crushed by large cornice pieces. Cornice fall can also trigger wet snow avalanches on the slopes below.

    Cornice collapses almost always surprise people by breaking farther back from the edge and/or wider than expected. If your route takes you along a corniced ridge, keep exposed rocks or trees between you and the cornice edge. Also, be wary of traveling on slopes below large cornices. It's best to avoid these slopes, but if really must travel a slope below a large cornice, spend as little time as possible doing so.

    (3/25/2025) Cornice fall triggered a large wet loose avalanche on a NE aspect. Donner Peak, Donner Summit area, CA

    Photo: Public

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