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Out of date — this forecast expired 6 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Triggering an avalanche continues to become increasingly unlikely but is still not an impossibility. Do not underestimate potential avalanche size even though LOW avalanche danger exists for all elevations. Normal caution is advised.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    2

    As triggering an avalanche associated with the recent persistent slab problem continues to become increasingly unlikely, normal caution becomes the travel advice. Isolated areas of unstable snowpit test results continue to trickle in while the vast majority of data indicates a stable snowpack in the majority of areas. Encountering isolated instability associated with the Dec 11 PWL buried in the bottom portion of the snowpack is unlikely but not an impossibility today. Be prepared with a route plan that allows you to scale back to sub 30 degrees slopes without steeper terrain above if the isolated collapse, crack, or unstable snowpit test result is encountered. Otherwise use the tactics of normal caution to lower the risk of an unexpected avalanche encounter.

Avalanche Discussion

* The Dec 11 PWL continues to decrease in reactivity.  Recent observations from around the forecast area are showing continued improving stability associated with this layer located in the lower portion of the snowpack on W-NW-N-NE-E aspects above and below treeline. Stability improvements have occurred more rapidly in the northern 2/3rds of the forecast area where the snowpack is deeper.  An isolated exception to this was reported yesterday from the Deep Creek drainage. In the southern 1/3rd of the forecast area, especially to the east of the Sierra Crest, the snowpack remains overall shallower and weaker. Strength gains on this weak layer have been observed to be comparatively slower on the eastern side of the Carson Pass and Ebbetts Pass areas.

*Recent periods of moderate speed SW and NE-E ridgetop winds have not been observed to create any problematic areas of drifting snow or subsequent wind slab formation.

* Faceting is beginning to form in some locations around the recently formed rain crust that exists in the upper snowpack in areas below about 7,800' to 8,200'. 

*A variety of snow surface conditions exist. Some soft snow remains on sun and wind sheltered upper elevation slopes. In wind exposed areas expect to encounter wind-scoured, wind-packed, and/or rain crusted surfaces.  Very superficial surface melt-freeze has occurred on slopes with direct sun exposure. The above noted rain crust is widespread and sometimes breakable, sometimes supportable.

Regions covered