Central Sierra Nevada

Problemas de aludes

• 

  Wind Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alta montaña
  • Límite del bosque
  • Bajo el límite del bosque

  Probabilidad

  Likely

  Tamaño

  2

  The wind slabs that have formed on leeward aspects since noon yesterday will remain fragile today. Human triggering of these wind slabs will remain likely. Most avalanches that result from the failure of these wind slabs should fail at or above the old snow surface; however, some of them could step down into older snow layers in areas where the new wind slabs exist on top of old hard slabs. The most sensitive wind slabs will exist on wind loaded N-NE-E aspects and cross loaded NW and SE aspects in near and above treeline terrain. These winds slabs could easily measure 2-3 ft in thickness or more in heavily wind loaded areas, and avalanches involving them could entrain enough snow to bury a person.

  Cornices above a slope, wind ripples, drifts, current wind loading, and other signs of wind loading can all serve as clues to help recognized slopes where wind slabs may exist. If a near or above treeline area looks nicely filled in and smooth and rounded, wind slabs likely exist in that area. Today is a good day to exercise some patience and avoid slopes where wind slabs may exist instead of letting the excitement of early season snow lead to poor decision making. 

• 

  Wet Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alta montaña
  • Límite del bosque
  • Bajo el límite del bosque

  Probabilidad

  Possible

  Tamaño

  1

  Loose dry snow sluffs will remain possible today. These sluffs could entrain all of the new snow and slide on the old snow surfaces or only involve a portion of the new snow and fail within the new snow. Steep slopes in near and below treeline terrain on NW-N-NE-E aspects sheltered from the winds hold the best potential for these kind of instabilities since they had more previous snow coverage. These instabilities could also exist on other near and below treeline aspects, but they will be more isolated and smaller on the SE-S-SW-W aspects due to the fact that most of those aspects did not have snow cover prior to this storm.

• 

  Loose Dry

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alta montaña
  • Límite del bosque
  • Bajo el límite del bosque

  Probabilidad

  Possible

  Tamaño

  1

  While loose dry sluffs will represent most of the non wind slab instabilities today, small and isolated storm slabs may exist on the near and below treeline NW-N-NE-E aspects in areas where the most new snow fell and where some consolidation has taken place in the new snow. Some uncertainty remains about how widespread these small storm slabs may be, but human triggering of these storm slabs will be possible today if one finds an area where they exist. These small slabs could fail on the old snow surfaces below them or within the new snow.