Bulletin d’avalanche

Central Sierra Nevada

Sierra Avalanche Center
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Danger d’avalanche

Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
3 · Marqué
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Périmé — ce bulletin a expiré 6 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Increased warming today means that loose wet avalanches will become likely on sunny slopes as the day warms up. Some fragile slabs of wind drifted snow may also still linger at on leeward aspects. CONSIDERABLE avalanche danger exists at all elevations. 

Problèmes avalancheux

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1

    Today's forecast calls for decreased ENE winds and increased daytime temperatures. These warm temperatures combined with the strong March sunshine may cause enough rapid warming for loose wet avalanches to become more widespread later today on sunny E-SE-S-SW-W aspects. As the day warms, human triggered loose wet avalanches should become likely and some natural loose wet avalanches may be possible. These could entrain all of the new snow and would slide on the old crusts. They could have serious consequences especially on long, steep, sunny slopes where they could run farther and entrain more snow.

    Traveling before the snowpack warms up or on colder northerly facing aspects could lead to finding colder softer snow and avoiding potential loose wet problems. As soon the snowpack starts to show signs of warming like roller balls or pinwheels, dripping trees, or wet sticky surface snow, it is time to move to lower angle slopes, colder aspects, or head to the lake for a picnic.

  • Wind Slabs

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

    The slabs of wind drifted snow that exist on SE-S-SW-W-NW aspects should become more difficult to trigger as the ENE winds decrease and wind-loaded slows down. Still, it may be possible for a person to trigger a wind slab avalanche today especially on wind-loaded sun-exposed slopes or in cross-loaded gullies. These wind slabs could measure a few feet in depth and could involve enough snow to bury or injure a person.

    Identify where wind slabs may exist by using clues like cornices above a slope, drifted snow, and other wind created textures. These areas have the best chances for finding variable wind affected snow and unstable wind slabs. Lower angle more sheltered terrain will hold more consistent and enjoyable snow. 

Avalanche Discussion

* On Relay Peak yesterday, skier-triggered shooting cracks and whumpfing occurred on a cross-loaded SE facing gully. 

* Yesterday, observers noted continued strong ENE winds on Relay Peak and Flagpole Peak. Less wind existed on Silver Peak. In all three areas, new snow still remained available for transport and a mix of scoured surfaces and wind-affected surfaces existed on exposed slopes.

* A ski kick on a steep N facing below treeline slope on Silver Peak triggered a small loose dry sluff yesterday morning. 

* By yesterday afternoon observers noted some signs of warming including sticky wet snow on sunny SE-S aspects on Silver Peak and some small roller-balls on S aspects of Relay Peak.  

Régions couvertes