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

Human-triggered wind slab avalanches remain possible today in certain areas. Pockets of MODERATE avalanche danger exist on wind-loaded NW-N-NE-E-SE aspects 35 degrees and steeper in near and above treeline terrain. Convex rollovers, areas near rocks, unsupported slopes, couloirs/gullies, and other complex terrain represent the most likely places to find lingering wind slabs.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2

    Wind slabs should grow more difficult to trigger today, however human-triggered wind slabs will remain possible in certain areas. Convex rollovers, areas near rocks, unsupported slopes, couloirs/gullies, and other complex or extreme terrain on wind-loaded NW-N-NE-E-SE aspects represent the best places to trigger wind slabs, and the places they take longest to stabilize. These wind slabs measure 1 to 2 ft. in depth, and avalanches resulting from their failure could involve enough snow to bury a person especially in the most heavily wind-loaded areas or in areas where terrain traps magnify the consequences of the wind slabs. A mix of old crusts and soft snow layers at the base of the wind slabs can serve as the weak layer. If a person does trigger a wind slab in one of the places where they remain sensitive, these slabs can break above the person who triggers them.

Avalanche Discussion

Yesterday observations on Castle Peak still revealed instabilities associated with wind slabs on wind-loaded slopes. Skier and small cornice piece triggered shooting cracks occurred on wind-loaded N-NE-E aspects in near and above treeline terrain. One test slope also slid with a 14 to 16 inch slab. The wind slabs in this area rested on top of a mix of old crusts and a layer of softer snow at the base of the wind slab. Across I-80 on Wildflower Ridge (Mt. Judah) large cornice pieces did not trigger cracking or slab failures in the slopes below. Snowpit data from near Billy's Peak in the Deep Creek drainage showed increasing stability. Observations from Tamarack Peak and the east ridge of Relay Peak in the Mt. Rose area also did not reveal signs of instability.

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