Bollettino valanghe

Central Sierra Nevada

Sierra Avalanche Center
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Pericolo valanghe

Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
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Non aggiornato — questo bollettino è scaduto 6 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Firm surface conditions early this morning will give way to snow surface melt and the possibility of loose wet snow avalanches at all elevations as the day progresses. MODERATE avalanche danger will exist today at all elevations once the surface crust melts away, exposing areas of deep wet snow.

Problemi valanghivi

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1

    Cloud cover decreased substantially after midnight last night allowing for radiational cooling of the snowpack. This combined with below freezing air temperatures at nearly all locations early this morning is expected to have lead to a strong overnight refreeze of the top several inches of the snowpack. Rapid snow surface melt fueled by the late April level of incoming solar radiation will melt away this surface crust today, exposing deep wet snow, and opening the door for loose wet snow avalanches as the day progresses. A loose wet avalanche problem is expected today on all aspects at all elevations. Avalanche size is expected at D1 to D2, depending on what the terrain is capable of producing.

    Avoid travel in avalanche terrain on slopes where marginally supportable to unsupportable deep wet snow exists. Today's winds may create some cooling and slow melt rates this morning directly along the ridgetops, but not mid slope or below.

Avalanche Discussion

* Diurnal melt-freeze conditions exist on all aspects.

* Observations made yesterday on Silver Peak (Pole Creek area) showed snow surface melt occurring at the mid to lower elevations traveled despite substantial cloud cover. By 10 am, E aspects at 8,000' held 2 inches of surface wet snow over a weakening but still supportable melt freeze crust. About 3 feet of residual, non-refrozen wet snow existed below the surface crust.

* Signs of layer consolidation from recent melt and rain have been observed in the top few feet of the snowpack on all aspects, minimizing the concerns for additional wet slab avalanches.

Regioni coperte