Bulletin d’avalanche

Central Sierra Nevada

Sierra Avalanche Center
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Danger d’avalanche

Thu
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré
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Périmé — ce bulletin a expiré 3 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

New snow and wind yesterday afternoon and last night continued the formation of cohesive slabs of wind drifted snow on the downwind side of ridgetops and in gully features. Warming air temperatures and decreasing cloud cover as the day progresses may create areas of unstable surface wet snow. Anticipate encountering areas of unstable snow today near cornice features and on sun exposed slopes.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1.5–2

    The combination of new snow and SW wind created conditions for wind slab avalanches to occur yesterday. Another round of new snow and SW to S wind yesterday afternoon and last night is keeping the potential for unstable wind slabs ongoing today.

    Cornices above a slope or gully wall, wind drifts, blowing snow, wind-created snow surface textures, recent avalanches, and snow surface cracking all provide clues to identify which slopes may hold unstable wind slabs. Identify specific areas of concern and consider avoiding them.

    (2/20/2024)

    This wind slab avalanche was skier triggered yesterday in a cross-loaded gully on the south side of Mount Rose, NV at around 9,000'. Crown depth was reported at 1 to 2 feet. Photo: Public

    Natural wind slab avalanches were reported yesterday from the Blue Lakes area south of Carson Pass, CA.

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2

    As cloud cover decreases today, areas of unstable surface wet snow may form on sun exposed slopes. Cloud cover is forecast to clear from east to west across the forecast area today. Maximum daytime air temperatures are expected to reach near to above freezing today below 8,000'. As a result, wet snow instability is expected to form first along the eastern side of the forecast area below about 8,000'. Wet snow instability may spread to higher elevation areas and to locations further west today depending on cloud cover and the rate of warming.

    Look for clues such as roller balls and pinwheels, either falling off of rocks and trees or triggered by backcountry travelers. Consider moving to less steep terrain in areas where these signs of surface wet snow instability are present. Keep in mind that long slopes with sustained slope angles of 35 degrees or steeper will be capable of producing larger wet loose avalanches.

    (2/20/2024)

    Surface wet snow developing on sun exposed E to SE aspects below about 7,200' at 11:45 am. Hidden Peak, West Shore Tahoe area, CA

    Photo: Sierra Avalanche Center

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