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

  Possible

  Dimensione

  3

  Wind slabs from the Sunday/Monday storm continue to gain strength with snowpack tests showing good bonding in many areas.  In isolated areas throughout the forecast area, recent human triggered avalanche activity and snowpack tests show that these wind slabs still remain a problem.  Areas of greatest concern are steep unsupported terrain and complex terrain with many trigger points on NW-N-NE-E-SE aspects near and above treeline.  Large loads may be required to trigger some of these wind slabs like multiple people on a slope at a time or large cornice fall.

  Identify and avoid steep wind loaded terrain. Use clues such as recent test slope failures, cornice formations, wind pillows, snow surface scouring and snowpack tests to determine where suspect wind slabs exist.  Practice safe backcountry travel protocols:  only expose 1 person on a slope at a time, use clear communication within your group, and regroup in safe areas away from avalanche runout zones

• 

  Loose Wet

  N

  NE

  E

  SE

  S

  SW

  W

  NW

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

  Probabilità

  Possible

  Dimensione

  2

  Warming temperatures, light winds, and full sun today will make loose wet avalanches possible on E-SE-S-SW-W aspects at all elevations and on NW-N-NE aspects below treeline.  Most of these instabilities should be in the form of roller balls and pinwheels and could be both natural and human triggered.  Larger loose wet avalanches could become possible today that could entrain enough snow to bury or injure a backcountry user. 

  Timing is critical as daytime warming occurs today.  Shallow snow areas with rocks or vegetation may become unstable first.  Roller balls or pinwheels are a sign that the snow surface is loosing strength and that larger loose wet avalanches may become possible.  Avoid slopes steeper that 35 degrees or being under steep slopes as daytime warming occurs.