Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

Wed
Alpine
1 · Low
Treeline
1 · Low
Below
1 · Low
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Out of date — this forecast expired 3 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

A weak snowpack continues to exist throughout much of the forecast region.  There are limited areas where a strong slab layer exists on top of this weak snowpack.  Avalanche conditions are isolated to these areas where strong snow exists on top of weaker snow until our next storm arrives.  Limited snow coverage is available for over the snow recreation with early season conditions present.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    1–1.5

    Weak faceted snow that formed earlier in the season can be found near the ground of our shallow snowpack on NW-N-NE aspects.  This weak snow is mixed in with rain crusts near 8000', with mostly faceted snow and depth hoar existing above 9000'.  Long clear nights and low sun angles continue to promote the faceting process on these shaded slopes.  Recent storm snow over this past weekend added load to these weak layers and formed overlying stronger slabs of snow in some areas.  These weak layers are highly variable in distribution and strength.  There is a high level of uncertainty predicting exactly where or if persistent slab avalanches may occur and how much additional load will be required.

    Any snowpack collapses, whumpfing sounds, or shooting cracks represent signs of unstable snow. If you encounter any of these signs of instability, avoid NW-N-NE aspect avalanche terrain in the area.

Avalanche Discussion

1 to 2 feet of snow can be found on NW-N-NE aspects above 8000' throughout the forecast region. Continuous snow cover starts around 7,200' to 8,000' along the Sierra Crest and 8000’ to 8500’ in the Carson Range. There is a lot of variability in the structure of the existing snowpack depending on elevation and location with concerning weak layers in some areas on NW-N-NE aspects. Some locations are thick rain crust either with or without a thin layer of facets. Some locations are a mix of layers of rain crusts and faceted snow. While other areas are all faceted snow and depth hoar without any crusts. There is generally little to no rain crust within the snowpack above 8,800' to 9,000'.

Previous NE wind events scoured the upper portion of many wind exposed slopes down to rock, dirt, and/or ice before the recent snowfall. Despite this scouring, weaker faceted snow persisted on the lower portions of many slopes. A much thinner snowpack or bare ground exists across E-SE-S-SW-W aspects.

While the snowpack has become more usable for over the snow travel, there is still the potential to hit many obstacles (rocks, logs, etc.) that are barely covered. Areas with a supportable rain crust below the recent new snow are the most usable. If you are traveling on snow for recreation, you should come up with a daily travel plan based on the current conditions and associated hazards. Anticipate encountering a different snowpack structure and a different set of travel conditions if you are moving from one place to another around the forecast area.

Regions covered