Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

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Out of date — this forecast expired 11 years ago.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

Highlights

Avalanche danger remains LOW for all elevations and aspects. Small minor loose wet instabilites may form in response to daytime warming. Normal caution is advised.

Avalanche problems

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    1

    A strong snow surface refreeze is expected to have occurred last night. This is due to radiational cooling under mostly clear skies with air temperatures at to a few degrees above freezing. As daytime warming progresses, areas of wet surface snow will form in all but the most heavily shaded areas. The lack of snow cover remaining on the vast majority of SE-S-SW aspects will limit the amount of instability that forms today. Of the slopes with continuous snow cover, E and W aspects will experience the greatest amount of wet snow formation with lesser amounts on NW-N-NE aspects. Human triggered roller balls are the expected extent of wet snow instability today. Isolated human triggered loose wet avalanches could occur on slopes 37 degrees and steeper, but are expected to be very small and with little consequence if size and type are the only factors. Secondary terrain hazards such as cliffs and terrain traps below always hold the potential to greatly magnify consequences of an avalanche that would otherwise be too small to bury or injure a person.

Avalanche Discussion

Observations made yesterday on Mt. Judah (Donner Summit area) revealed that wet snow was present on all aspects at mid day up to the summit at 8,200'. Recent new snow, now settled to around 0.5 inch in most areas was rapidly assimilating with the crust and wet snow in the top 6 inches of the snowpack. Minor skier triggered roller balls occurred while descending the E face of Mt. Judah at 12:30 pm. Conditions were marginally skier supportable at that time. Isolated, localized wet snow collapse was triggered three times while skinning through an open, low angle E aspect at 7,860' at 1 pm. Snowpack collapse was occurring within surface wet snow. Overall, evidence of wet snow instability was minor and localized at mid day.

Significant melt out has occurred on most SE-S-SW-W aspects in this area. On these aspects large areas of bare ground exist with a few sizable snow patches remaining in isolated locations. In general, continuous snow cover in the Donner Summit area is limited to NW-N-NE-E aspects. This is also the case in most other portions of the forecast area.

Regions covered