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

  Possible

  Tamaño

  2

  Despite the decrease in wind, expect to find slabs of wind drifted snow and fragile cornices lingering on wind-loaded and cross-loaded NW-N-NE-E-SE aspects. These wind slabs should be slightly more difficult to trigger today, but some of them could still break several feet deep and could involve enough snow to bury a person or a car (D2-D3).

  Smooth pillows of wind drifted snow on a slope, scoured areas on the ridge above a slope, and cornices hanging over the slope can all indicate the presence of wind slabs. Identifying where unstable wind slabs may exist can help reduce your exposure to this avalanche problem. Areas sheltered from the winds will hold softer less wind-affected snow. 

• 

  Storm Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

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

  Probabilidad

  Unlikely

  Tamaño

  2

  Weak sugary snow still exists underneath 3 to 5 ft of new snow in some areas on near and below treeline NW-N-NE aspects. On Sunday parties reported whumpfing on this layer and one avalanche may have occurred on Powderhouse Peak. Since then, signs of instability have decreased and evidence now indicates that getting enough force through the upper snowpack to break this layer would be difficult. Triggering a deep slab avalanche may be unlikely at this point, but it is not impossible especially with a larger trigger like multiple people on the same slope or a large cornice failure or with a smaller trigger at just the right spot/trigger point on some isolated slope. If a deep slab avalanche were to occur it would be very large and entrain all of the recent snow. 

  Due to the consequences of an unlikely but not impossible deep slab avalanche and some degree of uncertainty around this problem, it still warrants careful consideration. Identify where this layer may exist by probing into the snowpack or digging a snowpit. Recent avalanches, whumpfing, or snowpack collapse can indicate that you have found an isolated area where the deep slab instability remains active. If you have any doubts about the potential for a deep slab, go ahead choose a different aspect or more conservative terrain.