Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Near and above treeline, pockets of MODERATE danger exist along the Sierra Crest on NW-N-NE-E-SE aspects on slopes 35 degrees and steeper due to lingering wind slabs. For all other areas, avalanche danger is LOW.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2

    Pockets of unstable wind slab are expected to linger mainly along the Sierra Crest in near treeline and above treeline terrain on NW-N-NE-E-SE aspects. Triggering these wind slabs will likely be more difficult today than yesterday. Traveling on thin portions of the slab near trigger points such as exposed rocks or on slopes previously undercut by ski/snowmobile tracks will increase the likelihood of causing an avalanche. Very little evidence of instability is expected to exist in the backcountry today. Do not allow a lack of instability clues to lead to lazy or half hearted backcounty travel techniques. Anyone caught in an avalanche today will most likely be taken by surprise. Act like a pro by traveling one at time in avalanche terrain and moving from one high quality island of safety to the next.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    3

    Direct triggering of a deep persistent slab by a person on snowmobile, snowboard, or skies is very unlikely at this time. Above 9,000' to 9,500' on NW-N-NE aspects, a small amount of concern remains for the possibility of a triggered wind slab avalanche that creates sufficient force to collapse the weak layer of basal facets below. This would cause a large and destructive step down type avalanche event, involving nearly all of the existing snowpack. There is no mitigation technique for this avalanche problem, only avoidance. When evaluating northerly aspect slopes on the highest elevation peaks, consider the consequences of a large avalanche and do not let the call of fresh tracks cloud judgment.

Avalanche Discussion

Observations made yesterday in the Donner Summit, Ward Canyon, Carson Pass, and Mount Rose areas revealed storm snow totals of 12 to 24 inches along the Sierra Crest and 3 to 4 inches along the east side of Lake Tahoe. Travel in the above listed areas created isolated to frequent skier triggered cracking in wind loaded areas. Evidence of a recent natural avalanche was observed on Red Lake Peak (Carson Pass area). This avalanche occurred in near treeline terrain on a N aspect around 8,900' (more info). Snowpack failure was noted as occurring on a layer of lower density storm snow beneath higher density wind slab. This weak layer was observed along the Sierra Crest around 1 foot deep between 8,000' and 9,000' and in the Mount Rose area around 6 inches deep.

Regions covered