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 11 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

LOW avalanche danger exists this morning. As the day warms up, some pockets of MODERATE danger may form on sun-exposed SE-S-SW aspects steeper than 35 degrees up to 9500 ft. due to the possibility of some small loose wet snow instabilities like pinwheels, roller-balls, and point release avalanches. Most of these loose wet snow instabilities should remain small and isolated, but a few could entrain enough snow to create issues for backcountry travelers on slopes that experience the most warming. 

Problèmes avalancheux

  • Loose Wet

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

    Warmer overnight temperatures should mean a weaker overnight refreeze for the snowpack. Today's warm temperatures and sunny skies will cause this weaker refreeze to thaw more quickly, and some loose wet snow instabilities may form on the sun-exposed SE-S-SW aspects. Most of the loose wet snow instabilities should manifest as pinwheels, roller balls, and point release avalanches (sluffs). They should remain small and isolated since the snowpack has already been through several melt-freeze cycles this week and since the Feb. sun remains relatively low in the sky. However, a few of these instabilities could entrain enough snow to cause issues for backcountry travelers in isolated areas or extreme terrain. As the snowpack continues to melt and refreeze, these wet snow instabilities will continue to decrease in size, distribution, and likelihood. 

Avalanche Discussion

Yesterday observations from Mt. Judah and Silver Peak both showed melt freeze crusts sitting above cold dry snow on the sun exposed SE-S-SW aspects. By midday the crusts had melted, and some small loose wet snow instabilities had started to form in the most sun exposed areas. On shaded northerly aspects, cold soft snow still existed on the surface in near and below treeline terrain sheltered from the winds. In near and above treeline areas exposed to the winds, a mix of scoured crusts, firm wind packed snow, and other wind sculpted features existed on the surface. Observations, ski cuts, and snowpit tests on the northerly aspects showed a well bonded snowpack and did not reveal any signs of instability on those aspects. 

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