Bulletin d’avalanche

Central Sierra Nevada

Sierra Avalanche Center
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Danger d’avalanche

Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
2 · Modéré
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Périmé — ce bulletin a expiré 10 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

This morning the avalanche danger remains LOW for all elevations and aspects. MODERATE avalanche danger will form on E-SE-S-SW-W aspects steeper than 35 degrees as human triggered loose wet avalanches become possible. Some small isolated wet snow instabilities may also form on northerly aspects. Most loose wet snow instabilities should remain small today but some could be large enough to pose a danger to backcountry travelers especially on slopes that receive direct sun and less wind today. 

Problèmes avalancheux

  • Loose Wet

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

    Warmer overnight temperatures and some cloud cover means less refreezing occurred last night. Today the increased cloud cover and stronger winds should also make the melting side of the melt-freeze cycle less active. Still enough warming could occur today for loose wet snow instabilities like small roller balls, pinwheels, and wet point releases to form on some slopes especially in areas that receive direct sunshine and less wind. Sun-exposed E-SE-S-SW-W aspects steeper than 35 degrees where the recent snow has not been through enough melt freeze cycles to create good drainage channels in the snow hold the best potential for loose wet avalanches today, but some wet snow could also form on more northerly aspects due to the increased cloud cover. In some areas where less new snow existed or where firm wind packed or scoured surfaces existed after the recent storm, the surface snow has already experienced enough melt-freeze cycles to form good drainage channels and some decent corn snow conditions may exist. In still other areas like some of the exposed upper elevation slopes where the winds and cloud cover keep the snow surface cooler, the snow surface may remain mostly frozen today. 

    Sinking into wet snow above boot-top height, small surface wet snow instabilities like pinwheels or roller balls, and other recent loose wet snow avalanches can all indicate that enough wet snow exists for problematic loose wet avalanches to occur. These clues usually indicate that the snow conditions have become less fun to recreate on as well. At this point finding a more frozen aspect or switching activities represents a great way to stay safe and keep having fun.

Avalanche Discussion

Yesterday observations from Red Lake Peak, Angora Peak, and areas west of Carson Pass showed wet snow on sun-exposed aspects by 11 am. In some places like the more exposed ESE-SE-S aspects on Red Lake Peak this wet snow rested on top of a supportable melt-freeze snow that showed signs of well developed drainage. In other places like the E aspects of Angora Peak and some of the SE-S facing slopes west of Carson Pass the recent snow became wet and sticky and human triggered pinwheels and roller balls up to 3 ft. in diameter occurred. Observations from other aspects on Angora Peak showed firm icy frozen melt freeze crusts on W aspects before 1 pm and a mix of firm wind packed surfaces and patches of soft snow on exposed NW-N-NE aspects. Observations on the northerly aspects of Angora did not reveal any signs of instability. 

Régions couvertes