Bulletin d’avalanche

Central Sierra Nevada

Sierra Avalanche Center
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Danger d’avalanche

Tue
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
2 · Modéré
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Périmé — ce bulletin a expiré 5 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Areas of unstable wet snow will develop today as the snow surface melts in response to daytime warming. This will lead to the development of a wet loose avalanche problem at all elevations. LOW avalanche danger will exist today on wind exposed slopes above treeline. MODERATE avalanche danger will exist for all other areas including wind protected slopes above treeline.

Problèmes avalancheux

  • Loose Wet

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

    Below freezing air temperatures last night were limited to locations above 8,500-8,800'. The strongest snow surface refreeze is expected above 9,000'. Below 8,500'-8,800' air temperatures were once again above freezing overnight. A decent but superficial snow surface refreeze is expected to have occurred on open slopes below 8,800'. This will have been driven by overnight radiational cooling of the snowpack under clear skies. Snow surface refreeze will be relatively weaker and thinner in areas under forest canopy where radiational cooling was less efficient.

    Wind exposed slopes will be slow to melt today while wind protected, sun exposed slopes are expected to melt rapidly today. This could put areas of firm frozen snow surface very close by to areas of deep wet snow where terrain features are blocking the wind and melt rates are faster. There is the potential for some cloud build ups and a slight chance for some very light rain/snow showers along the Sierra Crest south of Hwy 50 this afternoon, but wet snow is expected to form before this has an impact on melt rates.

    Once the supportable crust on the surface has melted away, the deeper wet snow below it that did not refreeze last night will be exposed. This will open the door to a wet loose avalanche problem. Once the surface crust is no longer supportable, exercise caution in or below avalanche terrain. Utilizing terrain that is less steep than 30 to 35 degrees and without steeper slopes above minimizes exposure to potential wet loose avalanches.

Avalanche Discussion

* Deep wet snow conditions have been reported for the past several days from late morning onwards on sun exposed, wind protected slopes.

* Spring melt-freeze conditions are fairly well established on most E-SE-S-SW-W aspects. 

* NW-N-NE-E aspects still remain in between winter-like snow and spring melt-freeze conditions with a surface crust over colder dryer snow in some places, especially at higher elevations.

Régions couvertes