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

  A poor snow surface refreeze is expected to have occurred last night in areas below 9,000' to 9,500'. Warm overnight air temperatures will have kept snow surface refreeze reliant on radiational cooling. In open areas below 9,000', snow surface refreeze that did occur is expected to be thin and superficial. Little to no snow surface refreeze is expected to have occurred in treed areas where the forest canopy inhibits significant radiational cooling. Rain on snow expected this afternoon will add additional free water to the snowpack. In many areas below 7,500' to 8,000', recent melt has established free water drainage from the snowpack and today's rain will drain from the snowpack fairly easily. In the 8,000' to 9,000' zone where free water drainage is not as well established, more loose wet instability could occur during rain on snow this afternoon, especially on W-NW-N-NE-E aspects.

• 

  Wind Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpin
  • Limite forestière
  • Sous la limite forestière

  Probabilité

  Unlikely

  Taille

  1

  Strong to gale force SW winds and up to a few inches of new snow beginning to accumulate above 8,000' late today and tonight will start the formation of small wind slabs in near treeline and above treeline terrain. This avalanche problem is expected to become increasingly widespread on NW-N-NE-E-SE aspects above 7,000' to 8,000' as wind slabs build over the course of this storm cycle. Use clues such as signs of avalanche activity from the last storm cycle, cornice formations, wind pillows below ridgelines, and blowing snow to determine the location of potentially unstable wind slabs.