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

Considerable avalanche danger exists due to wind slab, storm slab, and loose wet avalanche problems.  Wind slabs will be likely in near treeline and above treeline terrain.  Storm slabs will be possible in near treeline and below treeline terrain.  Loose wet avalanches will be possible at all elevations.  Natural triggered avalanches are possible and human triggered avalanches are likely.  Areas north of Tahoe City along the Sierra Crest received the most snow overnight with more avalanche concerns. 

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1

    Strong to gale force S winds have created wind slabs on W-NW-N-NE-E aspects in near treeline and above treeline terrain.  As winds shift towards the W today, wind slabs will also be possible on SE-S aspects in near treeline and above treeline areas.  If rapid warming occurs today due to solar radiation, these wind slabs could be further weakened and more prone to avalanching.  These wind slabs are expected to be larger along the Sierra Crest North of Tahoe City.

    Look for blowing snow, cornice formation, wind pillows, and evidence of previous wind loading.  Avoid steep wind loaded slopes and area below cornices.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    Loose wet avalanche activity will be possible on E-SE-S-SW-W aspects at all elevations and on NW-N-NE aspects in below treeline areas.  Depending on cloud cover in your area, rapid warming could occur starting mid morning due to solar radiation.  The new storm snow now sits on a thin firm sun crust on most aspects and elevations except North.  As this new snow warms up it will have an efficient bed surface to slide on.

    If the snow surface becomes wet, it is time to switch aspects to colder snow or leave the area.  Loose wet avalanches large enough to injure or bury a backcountry user are possible.  Look for evidence of roller balls or loose wet avalanches to determine what aspects and elevations are experiencing rapid warming .  Terrain traps, such as gullies, can magnify the consequences of even a small loose wet avalanche.   

  • Loose Dry

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    Storm slabs will be possible on all aspects in near treeline and below treeline terrain.  These storm slabs will be limited to areas N of Tahoe City along the Sierra Crest where the most snow fell overnight.  Rapid warming from solar radiation could make these storm slabs more prone to failure.  Look for cracking around skis or any signs of cohesion within the new storm snow.  Avoid slopes that show signs of unstable snow.

Avalanche Discussion

Observations were made and received from Elephants Hump (Carson Pass area) and Negro Canyon (Donner Summit area).  Strong SW winds were moving light amounts of snow at both locations.  Wind slabs were small and not found to be reactive at either area.  Very light snow showers were on and off on Carson Pass with long periods of partly sunny conditions.  A variety of sun crusts and melt freeze crusts exist out there with different levels of supportability.  At lower elevations on Donner Summit, supportable sun crusts provided good travel conditions on E-S aspects.   

Regions covered