Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Highlights

New snow and wind today will cause the avalanche danger to increase to CONSIDERABLE in near and above treeline terrain as slabs of wind drifted snow become a problem. Human triggered wind slab avalanches will become likely. In more sheltered areas storm slab avalanches may become possible resulting in MODERATE avalanche danger. Variability in snowfall amounts and intensity during the storm will introduce some uncertainty around today's avalanche problems. 

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1

    Continued gale force winds combined with new snow today will cause new wind slabs to form on leeward aspects. These slabs of newly drifted snow will likely form too fast to bond to the variety of old snow surfaces that they form on. Human triggered wind slab avalanches large enough to bury or injure a person will become likely by this afternoon. The largest and most fragile wind slabs will exist in near and above treeline terrain. Wind slabs could form on W-NW-NE-N-E-SE aspects and may exist in some unusual places due to the more southerly wind direction.

    Blowing snow, cornices above a slope, drifted snow, and other wind created features can provide clues as to where wind slabs may be forming. Use this information to avoid wind loaded areas in favor of more sheltered terrain today. Not only will this help reduce exposure to avalanche danger it will also help locate areas of better snow and less wind.

  • Loose Dry

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    Intense snowfall, variable snow levels, and other changes during the storm may allow some slabs of soft snow to form above weaker snow in some areas today. These possible storm slabs would exist in areas that receive the most new snow and highest snowfall rates. In other areas that experience less intense snowfall and less accumulation, smaller loose dry sluffs may occur instead of storm slabs. The variability associated with this storm introduces some uncertainty around which of these problems will be more prevalent. 

    Human-triggered shooting cracks, recent avalanches, or other clues like finding a softer layer of snow below a denser layer of snow can indicate that you are in an area where storm slabs may be a problem. Identify these areas and build safety margins that reduce your exposure to the potential hazard. 

Avalanche Discussion

Yesterday observers reported a small skier triggered wind slab on a test slope on Castle Peak, shooting cracks on a wind-loaded test slope on Andesite Peak, wind slabs above softer snow on Judah, stubborn hard wind slabs in Munchkins, thin reactive wind slabs near the summit of Rubicon, and some reactive wind slabs and unstable test results from Tallac and around Ebbetts Pass. A high degree of variability existed in terms of the size and reactivity of wind slabs. Snow surfaces in these exposed near and above treeline areas ranged from scoured rain crusts to firm wind buff to hard wind slab to sastrugi covered areas. Strong winds and blowing snow were reported all along the Sierra Crest in near and above treeline areas. 

Soft unconsolidated snow and significant signs of settlement and consolidation existed in more sheltered areas on northerly aspects above 7500 ft. along the Sierra Crest and in the Ophir Creek drainage.

Below 7500 ft. observers reported wet snow surfaces.

 

Regions covered