Central Sierra Nevada

Problemi valanghivi

• 

  Wind Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alta quota
  • Limite del bosco
  • Sotto il limite del bosco

  Probabilità

  Likely

  Dimensione

  1–2

  Wind slab avalanches were triggered each of the last two days and this instability remains ongoing as blowing snow continues to drift and deposit onto leeward slopes. Wind slabs have become increasingly widespread over the last 24 hours. These wind slabs have formed mainly above treeline and near treeline on NW-N-NE-E-SE aspects, but maybe encountered anywhere wind drifted snow has deposited.

  Look for areas of blowing and drifting snow and identify where it has deposited as a wind slab.  This will be most prevalent on slopes adjacent to or below cornices and wind pillows. Move around these areas with an avoidance mindset.

  

• 

  Deep Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alta quota
  • Limite del bosco
  • Sotto il limite del bosco

  Probabilità

  Possible

  Dimensione

  2–3

  Deeply buried weak layers are still an avalanche concern in the snowpack.  The most recent reported avalanche of this type was triggered Saturday on a NE aspect on the NE fringe of the forecast area. Unstable snowpit tests were identified yesterday on the eastern edge of the forecast area in Ophir Creek, NV. This particular avalanche problem is mainly an issue in areas where the snowpack was shallow prior to this last storm cycle such as along the eastern fringes of the forecast area. This includes portions of the Carson Range on the NE, E, and SE sides of Lake Tahoe and locations east of the Sierra Crest in the Luther Pass, Carson Pass, and Ebbetts Pass areas.

  This is a challenging avalanche problem to manage as signs of instability aside from avalanche activity do not often readily present themselves. Scale back terrain choices if you are traveling in an area with recent reported avalanche activity or any areas where the snowpack was shallow prior to the last storm cycle. The easy way to avoid this avalanche problem is by either avoiding NW-N-NE aspects and recreating on any of the other aspects or by utilizing only sub 30 degree angle slopes on NW-N-NE aspects without steeper terrain above or to the side.