Central Sierra Nevada

Problèmes avalancheux

• 

  Loose Wet

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpin
  • Limite forestière
  • Sous la limite forestière

  Probabilité

  Possible

  Taille

  1

  For the second night in a row, conditions were not ideal for snow surface refreeze with cloud cover and above freezing air temperatures at about 8,200' and below. Snow surface melt rates are expected to be fairly slow today with loose wet avalanches eventually becoming a problem on all aspects and at all but the highest elevations. Avalanche size is generally expected at D1 with up to size D2 possible. How quickly this avalanche problem develops will be dependent on the strength of the surface refreeze and daytime melt rate. Rain below 7,500' may help get this avalanche problem going today.

  Continuously monitor snow surface supportability and surface crust strength and thickness. When the surface crust loses supportability or melts away exposing deeper wet snow, the loose wet avalanche problem is present and it is time to exercise options to adjust terrain choices accordingly.

• 

  Wind Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpin
  • Limite forestière
  • Sous la limite forestière

  Probabilité

  Possible

  Taille

  1

  Following the onset of new snowfall, wind slabs will become an increasing avalanche problem late today, tonight, and into tomorrow morning. SW winds are expected to drift new snow onto NW-N-NE-E-SE aspects in near treeline and above treeline areas, creating unstable wind slabs in lee areas. Avalanche size is expected at D1 late today and increases to size D2 overnight.

  Identify the areas of concern where unstable wind slabs may exist. Use clues such as areas below cornices, wind pillows, and snow surface texture to identify the likely location of wind slabs. Move around these areas cautiously and with an increased margin for error.