Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
View on map

Avalanche danger

Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
Open full map
Out of date — this forecast expired 9 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Human triggered wind slab avalanches and small loose snow sluffs will remain possible today. MODERATE avalanche danger exists in near and above treeline terrain today with LOW danger in below treeline areas. Carefully evaluate snowpack and terrain before committing to any slopes and identify where avalanche problems may exist. Use this information to avoid slopes where avalanche problems may exist.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    Increased winds today combined with soft snow on many windward aspects means another round of wind-loading and wind slab formation. Human-triggerable wind slab avalanches will remain possible in near and above treeline terrain today. These could include larger wind slabs formed by SW winds lingering on NW-N-NE-E-SE-S aspects that may grow larger today due to additional loading. Wind slabs formed by NW, NE, and SE winds in the last 24 to 36 hours could exist on all other aspects as well. Many of wind slabs should remain smaller and exist near ridgelines, but some could be large enough to bury or injure backcountry travelers. The most fragile wind slabs will exist in the places most exposed to wind-loading and in terrain like gullies, couloirs, unsupported slopes above cliffs, and other steep, complex, and wind-loaded terrain.

    Use clues such as blowing snow, cornice formations, and wind pillows to help identify recently wind-loaded slopes where unstable wind slabs may exist. Then use this information to plan a backcountry travel route that avoids the potentially unstable wind slabs and utilizes more sheltered terrain where better snow for recreation will exist.

  • Wet Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    Some small and mostly inconsequential loose snow sluffs could still remain possible on steep sheltered slopes. Most of these would occur where the coldest and least cohesive snow exists on NW-N-NE aspects. 

Avalanche Discussion

A snowmobile avalanche class reported seeing a recent wind slab avalanche in the Blue Lakes area that may have occurred yesterday on an E facing aspect at 8200 ft, and they reported seeing significant wind transport in that area yesterday. Observations from Andesite Peak, Negro Canyon, Ophir Peak, and Blackwood Ridge all found soft unconsolidated snow on sheltered W-NW-N-NE-E aspects and a mix of wind-affected snow including firm wind-packed snow, wind scoured surfaces, and soft wind slabs on exposed near and above treeline slopes. Tests and observations in most of these places did not reveal many signs of instability on sheltered slopes. Cornices above test slopes in Negro Canyon still broke easily and well away from their edges. Some small skier-triggered cracking occurred near the ridgeline on Ophir Peak, and one isolated whumpf occurred on Andesite Peak. Ski cuts on steep E-NE-N facing slopes in Negro Canyon did release small loose dry sluffs that entrained the top 4-5 inches of snow. 

Regions covered