Boletín de aludes

Central Sierra Nevada

Sierra Avalanche Center
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Peligro de aludes

Alta montaña
2 · Moderado
Límite del bosque
2 · Moderado
Bajo el límite
2 · Moderado
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Desactualizado: este boletín caducó 7 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Snow surface melt leading to loose wet avalanche problems is expected today at all elevations, mainly in areas of direct sun exposure. Most avalanches will be fairly small, but avalanches large enough to bury a person could occur. MODERATE avalanche danger exists at all elevations.

Problemas de aludes

  • Loose Wet

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1

    Snow surface refreeze is expected to have occurred last night due to radiational cooling under mostly clear skies despite above freezing air temperatures. These same mostly clear skies and well above freezing air temperatures at sunrise today will allow snow surface melt to occur quickly on E-SE-S-SW-W aspects. Fairly widespread loose wet avalanche problems are expected today with avalanche size mostly at D1 with up to D2 possible. The still fairly low sun angle and shorter length of daylight hours this time of year are expected to keep problematic amounts of surface wet snow from forming today on NW-N-NE aspects.

    Areas around exposed rocks in direct sun is where the greatest amount of incoming solar radiation and snow surface heating will occur. Rollerballs are an indication that instability associated with loose wet avalanches is forming. Choose terrain wisely considering how consequences from otherwise small avalanches can be greatly exacerbated by involvement with trees, rocks, cliffs or terrain traps below.

      Photo: Intentionally triggered size D1 loose wet avalanche yesterday following an unforecast light rain event. Details below.

Avalanche Discussion

* An unforecast light rain event early yesterday morning brought 0.1 to 0.3 inches of liquid water to areas extending from the northern boundary of the forecast area down to around Carson Pass.

* In areas that received light rain, the top half to 1 inch of the snowpack was wet yesterday on all aspects up to at least 8,800'. This is expected to have refrozen as surface crust last night.

* A small size D1 loose wet avalanche was intentionally skier triggered yesterday on the lower northern flanks of Donner Peak (Donner Summit area) on a NW aspect at around 7000' on a 35-40 degree slope.

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