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

Points saillants

LOW avalanche danger will transition to MODERATE avalanche danger at all elevations today in response to daytime warming. As last night's snow surface refreeze becomes unsupportable, a loose wet avalanche problem will develop at all elevations.

Problèmes avalancheux

  • Loose Wet

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

    Increasing cloud cover and above freezing air temperatures last night are expected to have allowed for a weaker snow surface refreeze last night as compared to 24 hours ago. As daytime warming progresses, a loose wet avalanche problem will develop on all aspects at all elevations. Avalanche size is generally expected at D1 with the possibility of an isolated size D2.

    Be ready to exit avalanche terrain early in the day today, especially if last nights refreeze was not particularly strong or thick in your chosen area of travel. Continuously monitor snow surface supportability and surface crust strength and thickness. When the surface crust loses supportability or melts away and the deeper wet snow is exposed, the loose wet avalanche problem is present and it is time to adjust terrain choices accordingly.  Keep in mind that moderate to strong ridgetop winds may slow melt rates near the ridgetops while more rapid melt rates occur mid slope and below.

Avalanche Discussion

* Yesterday, very strong overnight refreezes were noted in the Donner Summit and Luther Pass areas. Supportable snow surface conditions lasted well into the afternoon hours on all aspects.

* Snow surface refreeze conditions last night were much less ideal than the night before due to building cloud cover and warmer air temperatures.

* Snowpack instability is expected to occur near the surface, with the deeper snowpack generally well bonded. The exception might be glide cracks.

Régions couvertes