Bollettino valanghe

Central Sierra Nevada

Sierra Avalanche Center
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Pericolo valanghe

Fri
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
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

There will be a longer window for travel in avalanche terrain today before unstable wet snow becomes a concern. Exit avalanche terrain before the snow surface becomes unsupportable. Once the surface crust melts away exposing deep wet snow or when signs of unstable wet snow such as rollerballs or pinwheels are occurring, wet loose avalanches are possible.

Problemi valanghivi

  • Loose Wet

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

    A strong but still superficial snow surface refreeze occurred last night at all elevations across the forecast area. As daytime warming progresses, the superficial snow surface refreeze from last night will eventually melt away and expose deeper residual wet snow. This will bring about the possibility of wet loose avalanches. Some of these avalanches could be large enough to cause problems for backcountry travelers, especially on long slopes where a wet loose avalanche will entrain more snow as it travels downhill. 

    Once the snow surface starts to become unsupportable it is time to think about avoiding slopes steeper than about 35 degrees. Pinwheels, rollerballs, sinking ankle-deep or more into wet snow when you step off of your equipment, and wet loose avalanches are all signs of unstable wet snow. Exit avalanche terrain before signs of deep or unstable wet snow develop.

    (4/12/2023)

    The superficial surface crust from overnight refreeze at just 3 inches thick as seen yesterday (Apr 12) at 9,200' on a SE aspect at 10:40 am. Below this very firm crust was deep residual wet snow waiting to become exposed as daytime warming and snow surface melt progressed. Rose Knob Peak, NV.

    Photo: SAC

  • Cornices

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

    A lull in cornice fall activity is expected today due to the strong refreeze last night and cooler maximum daytime air temperatures today. The likelihood of this problem is expected to increase again tomorrow through Sunday. Large to massive blocks of snow falling off of overhung cornice sections along ridgetops could cause problems on their own or trigger wet snow avalanches on the slopes below.

    Most cornice fall accidents occur during ridgetop travel and take the party involved by surprise. Stay well back from cornice edges, keeping exposed rocks or trees between you and the cornice edge. Consider avoiding travel on slopes below cornices.

    (4/12/2023)

    A recent cornice collapse along the ridgetop west of Rose Knob Peak, NV.

    Photo: SAC

Avalanche Discussion

  • Some glide cracks have formed on steep slopes in rocky areas. Like cornice fall events, the exact timing of glide crack avalanches is notoriously difficult to predict. Due to the uncertainty, consider avoiding travel on or below slopes with glide cracks.

Regioni coperte