Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

Sat
Alpine
2 · Moderate
Treeline
2 · Moderate
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Out of date — this forecast expired 3 years ago.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

New snow accumulation over the last 24 hours along with strong winds have created slabs of wind blown snow.  In some areas, these new wind slabs exist on top of a very weak snowpack.  Avalanches are possible today.  Limited terrain continues to exist for over the snow recreation.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2

    Recent new snow and strong SW-W winds have created wind slabs in near and above treeline areas.  Most locations throughout the forecast area received 2 to 3'' of new snow overnight with small wind slabs expected for today.  Areas that received the higher end snow totals, such as Carson Pass which received 6'' of new snow, larger wind slabs will be possible.  This includes below treeline terrain.  These larger formed wind slabs could cause failure deeper into the old weak snow near the ground.  These avalanches would be larger and wider having increased consequences.

    Look for blowing snow, new cornice formation, snow surface signs, and wind pillows as to where wind slabs may have formed.  Any cracking, collapsing, or whumpfing sounds would be signs that you are overloading the weak layer below the new storm snow.  Avalanches could occur in starting zones at the top of slopes, or potentially midslope where old weak snow exists.  Very low snowpack conditions continue and even a small avalanche could have large consequences with all the obstacles present.

Avalanche Discussion

Throughout the forecast region, 1 to 2 feet of snow can be found on NW-N-NE aspects above 8000'.  The snowpack is made up of rain crusts and weak faceted snow.  At elevations around 8000', mostly firm supportable rain crusts are present.  At higher elevations above 8500', a very weak snowpack structure exists and is made up of facets and large depth hoar.  Previous NE wind events have scoured many wind exposed slopes down to rock, dirt, and/or ice.  Snow coverage and snowpack structure are highly variable throughout the forecast region.

Early season conditions exist with many obstacles (rocks, bushes, logs, open water, etc.) exposed or barely covered. Hitting one of these hazards could easily end your season before it even begins.  If you are traveling on snow for recreation, you should come up with a daily plan based on the current conditions and carry your normal backcountry kit including avalanche rescue gear (avalanche transceiver, probe, shovel).

Regions covered