Central Sierra Nevada

Avalanche problems

• 

  Wind Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  1

  A wind slab avalanche problem lingers due to recent new snow and SW winds. The vast majority of wind slabs exist near treeline and above treeline on NW-N-NE-E-SE aspects. Avalanche size up to D2 is possible. Some of these wind slabs may take on some wet slab characteristics, especially on SE aspects.

  Identify the specific terrain features where unstable wind slabs may exist. Ridgetop areas below cornice features and wind pillows are the most suspect. Approach travel near these features with caution, opting for more conservative terrain choices if signs of instability exist.

• 

  Loose Wet

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Likely

  Size

  1

  Today is expected to be one of the first days when the higher sun angle and higher levels of incoming solar radiation associated with March affect stability. Natural roller balls are expected as snow falls off of rocks and trees in sun exposed areas. Some of these roller balls may trigger loose wet avalanches. Human triggered loose wet avalanches are likely today in steeper, sun exposed areas. The majority of loose wet instability is expected on E-SE-S-SW-W aspects at nearly all elevations. Loose wet avalanches are expected to a much lesser extent on NW-N-NE aspects but may also occur in areas of sun exposure. Avalanche size is expected at D1 with the isolated possibility to size D2.

  If roller balls are present, this avalanche problem may soon follow. Avoid complex terrain and long steep pitches where this instability is present. Downslope hazards such as cliffs and terrain traps could greatly magnify the consequences of being pushed around by a small loose wet avalanche.