Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

Alpine
1 · Low
Treeline
1 · Low
Below
1 · Low
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Out of date — this forecast expired 10 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Avalanche danger is LOW for all elevations and aspects. A low likelihood, high consequence persistent slab avalanche problem remains on N aspects both above and below treeline in specific areas. Very isolated wind slabs may linger on any aspect in near and above treeline terrain.

Normal caution is advised for managing the wind slab problem. Extra caution and conservative terrain choices are advised for managing the persistent slab problem.

Avalanche problems

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    2

    The persistent slab problem remains a low likelihood, high consequence situation. The weak layer is faceted old snow buried 2 to 3 ft below the surface on N aspects along the northern portion of the Sierra Crest above 8,300', in the Mt. Rose area above 9,300', and in very isolated areas in the southern portion of the forecast area above 9,000'. Triggering has proven difficult, but day to day snowpit data continues to point out the potential for a fairly large avalanche occurrence.

    When dealing with persistent slabs most informal observations do not give reliable information and existing tracks do not indicate stability. In areas where this avalanche problem is likely to exist, consider what information is truly known vs unknown before committing to travel in N aspect avalanche terrain. The simple strategy is to avoid N aspects steeper than 30 degrees in known suspect areas. Otherwise, a fair bit of investigative work will be required to determine if the problematic snowpack structure exists on the slope of interest.

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    1

    Triggering an isolated wind slab avalanche is very unlikely today, but not all together impossible. Very, very isolated instability could linger in near treeline or above treeline terrain on any aspect due to recent shifting winds and blowing snow. Normal caution is advised for travel on recently wind loaded slopes.

Avalanche Discussion

Observations made and received yesterday from the Upper Meiss Drainage (Carson Pass area), Mt. Judah (Donner Summit area), and Lincoln Ridge (Yuba Pass area) revealed evidence of significant previous wind transport. Widespread areas of wind scouring were noted on all aspects, with pockets of high density wind deposited snow. Recently formed wind slabs existed but revealed no signs of instability. On Castle Peak (Donner Summit area), snowpit data collected on a N aspect at ~8,650' continued to point out the ongoing persistent slab problem.

The deepest and most usable snowpack within the forecast area exists along the northern portion of the Sierra Crest. Along the Sierra Crest south of Tahoe City, snowpack depths decrease, even at the highest elevations. Recent storms have added to the snowpack in all areas but many rocks and shallowly buried obstacles still exist. The Mount Rose area in the NE portion of the forecast area has decent snowcover, but impact with rocks remains likely at the lower elevations in this area as well.

All of the recent avalanche and snowpack observations submitted by local users have been greatly appreciated and have contributed towards producing the best possible avalanche advisories. Please continue to submit observations through the "submit observations" buttons found throughout this website.

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