Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

Alpine
1 · Low
Treeline
2 · Moderate
Below
2 · Moderate
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Out of date — this forecast expired 13 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

MODERATE avalanche danger continues near treeline and below treeline on NW-N-NE aspects on slopes 32 degrees and steeper due to ongoing persistent slab instability.

Current conditions are still very conducive to human triggered avalanches. Give this snowpack the respect it deserves. It is playing by its own set of rules.

Avalanche problems

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2

    Near treeline and below treeline slopes on NW-N-NE aspects that resisted scouring by the Nov 21-23 ENE gale force wind event hold significant amounts of faceted snow below the 9 day old storm snow. This is the Dec 7 persistent weak layer with an overlying slab. This weak layer is easily collapsed under the weight of a person and has shown the ability to propagate from tens of feet to hundreds of feet. Sizable human triggered avalanches are possible with triggering occurring either high on the slope, low on the slope, or remotely.

Avalanche Discussion

Persistent instability is just that. Day after day field observations continue to show ongoing evidence of instability associated with the faceted Dec 7 persistent weak layer. Collapse and propagation continue to occur along this weak layer. Whumphing and cracking have been impressive at times, even in areas close to the tracks of previous backcountry travelers in the immediate area. See below for more detailed information on recent observations from Upper Ophir Creek (Mount Rose area) and from the Deep Creek drainage.

There are a few areas where the shallow snowpack has enough structure or strength to keep a person from hitting the many rocks and/or logs below. In other areas the snowpack remains unsupportable and impact with rocks and/or logs is inevitable.

Regions covered