Central Sierra Nevada

Avalanche problems

• 

  Wind Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  1–2

  Ridgetop winds shifted last night from SW to NE and there was plenty of recent storm snow on the ground available for drifting. A patchy mix of wind scoured areas and drift deposited wind slabs are expected on all aspects in above treeline and near treeline terrain. Avalanche size up to D2 remains possible. Several wind slab avalanches were skier/snowboarder/snowmobiler triggered yesterday so signs of recent avalanches may be visible today.

  Use clues such as recent avalanches, blowing snow, cornice formations, wind pillows, and textured snow surfaces to determine where unstable wind slabs may exist. Move around these areas with caution. Avoiding wind loaded above treeline and near treeline areas in favor of more sheltered below treeline terrain will help limit exposure to the wind slab avalanche problem and may provide more consistent snow conditions.

  

• 

  Loose Wet

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  1–2

  As air temperatures climb above freezing today and sunny skies allow for strong incoming solar radiation, a wet loose avalanche problem will become possible. Avalanche size is expected at D1 to D2. The majority of wet loose avalanche problems will form on E-SE-S-SW-W aspects and to a lesser extent on sun exposed NW-N-NE aspects.

  As the snow surface starts to melt and become wet, recent new snow will show roller balls and pinwheels as indicators of developing instability. This avalanche problem will form quickest in wind protected areas near exposed rocks, eventually spreading to other areas as winds decrease and air temperatures continue to warm. Exercise caution on or below steep slopes where surface wet snow, roller balls, and/or pinwheels are present.