Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

A strong winter storm has started to impact our area with high winds and heavy snow expected.  Wind slab and storm slab avalanches will become likely today at all elevations.  CONSIDERABLE avalanche danger will exist today with avalanche danger expected to rise to HIGH tomorrow as this storm continues. 

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1

    Gale force SW winds will continue with increasing amounts of snowfall today and tonight.  Wind slab avalanches will be likely in near and above treeline areas where wind drifted snow has accumulated.  These wind slabs will be increasing in size throughout the day as additional snow becomes available for wind transport.  Natural wind slab avalanches will become possible today with human triggered avalanches likely.  These wind slab avalanches will become large enough to injure or bury a backcountry user.

    Look for blowing snow, new cornice development, and developing wind pillows.  Make a plan to avoid steep wind loaded terrain and run out zones below large cornices.   

  • Loose Dry

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1

    Storm slabs will become likely as snowfall rates and amounts increase into the afternoon hours.  These storm slabs will develop in near and below treeline areas where previous snow cover has existed.  Storm slabs are expected to continue to be a problem overnight and into tomorrow as this storm brings additional snow.

    Monitor new snow amounts while traveling in the backcountry.  Look for cracking or any signs of cohesion or slab formation within this new storm snow.  Utilize lower angle slopes and terrain features to limit your exposure to avalanche terrain. 

Avalanche Discussion

Observations were received yesterday from Relay Peak and Incline Lake Peak (Mt. Rose area), Meiss Meadows (Carson Pass area), and Echo Lake (Echo Peak area).  Continued monitoring shows the upper snowpack on northerly terrain in near and below treeline areas to be made up of weak crusts and loose sugary snow.  The strength and distribution vary from location, but still remain a concern with a large loading event arriving.

 

Our existing upper snowpack is made up of weak crusts and loose sugary faceted snow on northerly aspects in near and below treeline areas.  As this storm adds additional load to this weak snowpack structure, concern exists that these layers could fail and cause large deep slab avalanches.  With our current weather forecast, potential for these deep slab avalanches would begin overnight and into Sunday.  

Regions covered