Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
View on map

Avalanche danger

Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
Open full map
Out of date — this forecast expired 7 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

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.

Avalanche problems

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    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.

Regions covered