Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

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

New snow and strong winds have created slabs of wind drifted snow in exposed areas.  The new storm snow may have problems bonding to the old snow surface in many locations.  Watch for signs of unstable snow, like recent avalanches or cracking in the new storm snow, and move to lower angle terrain if you see instability.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2

    Wind slab avalanches continued to be reactive yesterday.  Gale force SW winds with gusts over 100mph overnight along with 2 to 8'' of light new snow have built out additional wind slabs on NW-N-NE-E-SE aspects.  Winds are forecasted to switch to the NW and eventually to the NE later today and remain strong enough to continue to transport snow.  Wind slabs could occur on any aspect in near and above treeline areas.  Where these wind slabs form on top of recently buried surface hoar, these avalanches could be wider and run longer distances than our typical wind slab avalanches.

    Look for recent avalanche activity, blowing snow, cornices, wind pillows, and snow surface clues as to where these wind slabs have formed.  Natural wind slab avalanches are not out of the question today.  Avoid terrain below steep wind loaded slopes and cornices.  Long shooting cracks, whumpfing sounds, recent avalanches with wide propagation, or any sort of remote triggering would indicate that the buried surface hoar is present and reactive. 

    (1/18/2023)

    D2 skier triggered wind slab avalanche.  1 to 1.5' deep.  Cindercone, Ward Canyon area.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2

    2 to 8'' of new storm snow has fallen overnight with many areas reporting up to 2 to 4’’, additional light snow is possible through this morning.  While this amount is on the lower end for storm slab development, this new snow has fallen on now buried surface hoar that developed on Monday and Tuesday nights.  Most of the avalanche activity associated with this weak layer should be in the form of loose dry sluffing with these small storm snow amounts.  These sluffs could entrain some snow and be able to run downhill long distances at fast speeds.  In some of the areas that received the most snow overnight, some small storm slabs could become possible.  As this new storm snow begins to settle and gain strength, more slab characteristics may begin to occur.

    Look for cracking around skis or shooting cracks while moving through terrain.  If you see any indication of slab development, utilize lower angle terrain to avoid this problem.  Be aware of terrain above and below you, loose dry sluffing could be large enough to take you for a ride downslope in steeper terrain.

Avalanche Discussion

  • A skier triggered wind slab avalanche was reported from the Ward Canyon area yesterday afternoon. 
  • Reports of widespread surface hoar have come in throughout the forecast region on most all aspects and elevations.  There is some uncertainty if any of this surface hoar has been destroyed by wind and/or sun pre storm and if this will develop into a persistent slab avalanche problem.
  • Thin sun crusts have started to develop on some sun-exposed slopes.

Regions covered