Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

MODERATE avalanche danger will exist at all elevations today due to lingering wind slab problems and loose wet avalanche problems that form in response to daytime warming. Warming could also weaken the lingering wind slabs in some areas. The largest avalanche problems will exist in areas where more snow accumulated during the recent storm like the Mt. Rose area and other high-elevation areas across the region. Identify where wind slabs and loose wet avalanches may exist and avoid those areas.

Avalanche problems

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    The intense spring sunshine and warm daytime temperatures should cause enough melting for some loose wet avalanches to become possible today especially in areas where storm snow from Wednesday and Thursday exists on the surface. As the sun and warm temperatures heat this snow up, it will warm up for the first time and will become wet and weak. Sun-exposed E-SE-S-SW-W slopes in the Mt Rose area and in other higher-elevation areas across the region hold the best potential for loose wet avalanches since more recent snow exists in those areas. Loose wet avalanches could also occur in areas where the sun and warmth melt through the exposed surface crusts and leave areas of deep wet snow on the slopes.

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    Wind slabs that formed during the storm still exist on wind-loaded and cross-loaded slopes. The largest of these wind slabs exist in near and above treeline terrain on wind-loaded W-SW-S aspects and cross-loaded NW and SE aspects in the Mt. Rose area and in other isolated high-elevation areas across the region where the most snow accumulated during the storm. Observations from yesterday indicated that some wind slabs also exist on cross-loaded N-NE-E aspects. Human triggered wind slabs may remain possible today. Most of these should remain small and not extend very far away from the ridgelines, but a few larger wind slabs could exist in isolated areas where the most snow fell. The most fragile wind slabs will exist on sun-exposed aspects where sun and daytime warming will weaken the wind slabs. Along the Sierra Crest where less storm snow accumulated, wind slabs should remain smaller and less likely to represent a significant avalanche problem.

     

Avalanche Discussion

Yesterday a snowboarder triggered avalanche was reported on an above treeline E aspect on Relay Peak. This avalanche measured about 1 ft in depth and 150 ft. in width. It appears that this wind slab had formed on a cross-loaded E aspect above a small cliff band. No injuries were reported. On Inline Lake Peak, wind slabs up to 16 inches in depth had formed on wind-loaded SW aspects. Ski kicks on these wind slabs triggered shooting cracks and some small test slope failures. Snow surface conditions varied from scoured icy crusts to wind packed surfaces in most areas. A few small areas of soft unconsolidated snow still existed on low angle slopes in below treeline areas sheltered from the wind. Observations on Jakes Peak found much less new snow and more exposed icy crusts. Surface conditions alternated between refrozen old snow and dust on crust conditions where new snow had accumulated. Some small wind slabs up to 4 inches deep did exist on NE aspects near the summit of Jakes. 

Regions covered