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 drifting of new snow has also created an avalanche problem. Cohesive slabs of locally deeper wind deposited snow could be encountered on the down wind side of ridge features and in gullies, mainly near and above treeline.

  Look for cornices and snow drifts to help identify where wind slabs might exist. Snow surface cracking within the new snow could be encountered and indicates instability. Consider avoiding areas that appear to hold slabs of wind deposited snow.

  

• 

  Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

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

  Probabilità

  Likely

  Dimensione

  1.5–2.5

  You could trigger a large avalanche today at or below treeline. Near and above 8,000' to 8,500', old weak faceted snow persists as a weak layer beneath the new snow. This weak snow exists around crust layers in the lower portion of the snowpack and at the ground. The location of this problem is near treeline and below treeline across NW-N-NE aspects. Recent rain has strengthened the old faceted snow in areas below 8,000', reducing the distribution of this avalanche problem. That said, if you find this avalanche problem and trigger it, you will be dealing with a large avalanche.

  Snowpack collapse, shooting cracks, and avalanches will be the signs that this avalanche problem is active in your location. Be careful with interpreting snowpit tests right now. You could easily get "false-stable" results if you don't dig in the right place. Don't discount moist facets, as they can still fail under a recent heavy load. Move carefully around the NW-N-NE aspect locations of concern. Keep in mind, you could trigger an avalanche from low on the slope due to where this weak layer is distributed.