Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

Alpine
1 · Low
Treeline
1 · Low
Below
1 · Low
Out of date — this forecast expired 11 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Avalanche danger is LOW for all elevations and aspects. Minor loose wet instabilities are expected during the afternoon hours. Loose wet avalanches large enough to bury or injure a person are unlikely. Normal caution is advised. Sufficient snow cover for avalanche activity on SE-S-SW-W aspects exists only in isolated portions of the forecast area. Much deeper, continuous snow cover exists on NW-N-NE-E aspects.

Avalanche problems

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    1

    With clearing skies overnight and near to below freezing air temperatures, a strong overnight snow surface refreeze is expected to have occurred due to radiational cooling. As daytime warming progresses, areas of surface wet snow will form on sun exposed slopes. Increasing cloud cover today is not expected to be as thick as yesterday and therefore will not have as great of an impact on slowing the melting process during the mid day and afternoon hours. With the snowpack already subject to periods of rain and prolonged melt earlier this winter, free water drainage from the snowpack is well established. With little to no snow cover on the vast majority of SE-S-SW-W aspects, instability concerns are confined to highly localized areas on those aspects. E aspects continue to hold significant snow cover around the vast majority of the forecast area and will experience surface wet snow formation up to several inches deep by this afternoon. With free water drainage well established, wet snow instability is expected to be limited to human triggered roller balls and human triggered loose wet sluffs in steep terrain that require a push to set into motion. Loose wet avalanches large enough to bury or injure a person remain unlikely at this time.

Avalanche Discussion

Observations made yesterday on Relay Peak (Mount Rose area) revealed that a strong snow surface refreeze had occurred in the area overnight. Increasing cloud cover during the morning hours greatly slowed the rate of snow surface melt. Travel on E-SE-S-SW aspects between 8,500' and 10,100' between 10 am and 1 pm revealed no more than 2 inches of wet surface snow on top of ski and boot supportable melt-freeze crust. No evidence of wet snow instability was observed prior to departure from the area at 1 pm. Snowpit data collected on an E aspect at 10,050' indicated that only the top 7 inches of the snowpack had been affected by melt-freeze at that elevation. Below the top 7 inches a well bonded, rounded snowpack with a temperature profile approaching isothermal was observed in the snowpit. Recent snowpit data collected on E aspects on Carson Pass and on Mt. Judah (Donner Summit area) at 8,900' and 8,100' respectively indicated that the full height of the snowpack had been subjected to melt-freeze.

Across the forecast area in general, sufficient snow cover for avalanche activity on SE-S-SW-W aspects exists only in isolated areas. Much deeper, continuous snow cover exists on NW-N-NE-E aspects.

Regions covered