Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

Alpine
4 · High
Treeline
4 · High
Below
4 · High
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Out of date — this forecast expired 8 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

HIGH avalanche danger continues for all elevations. Travel in or below avalanche terrain is not recommended. Maintain awareness of your location relative to avalanche terrain and keep a wide margin for error. Remain clear of avalanche runout zones.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    2

    Continued snowfall and gale force SW winds are drifting snow and keeping the wind slab avalanche problem ongoing. The vast majority of wind slabs exist near treeline and above treeline on NW-N-NE-E-SE aspects. Wind slabs may be encountered to a lesser extent on other aspects or in below treeline areas due to the strength of the wind and amount of recent snowfall. Avalanche size up to D3 is expected (could bury a car, destroy a house, or break a few trees).

    Be aware of the potential for avalanches from above running down into lower angle treed areas. Route plan carefully, anticipating low visibility obscuring overhead avalanche start zones when avoiding travel below avalanche terrain.

  • Loose Dry

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1

    Storm slab avalanches remain likely from high intensity snowfall and varying snow crystal types (including graupel) creating weak layers within the new snow. Storm slabs form in wind protected areas mainly near and below treeline and may be encountered on any aspect. Avalanche size up to D2 is expected (could bury or injure a person).

    Route plan carefully to avoid avalanche terrain. If areas of questionable slope steepness are encountered during travel, use an inclinometer to measure slope angle in order to assist in data based decision making. Allow a margin for error. Be aware of the potential for steeper slopes above.

Avalanche Discussion

* Snow levels peaked Thursday morning up around 8,500' to 9,000'. Rain soaked snow exists below the new snow from the past 24 hours in most areas.

* Several widespread graupel weak layers were reported yesterday within the new snow that accumulated during the past 24 hours.

* Signs of unstable wind slabs have been present in field observations during the past several days.

* Visibility in the backcountry has been poor with limited ability to see into avalanche start zones and assess for natural avalanche activity.

Regions covered