Central Sierra Nevada

Problemi valanghivi

• 

  Glide Cracks

  N

  NE

  E

  SE

  S

  SW

  W

  NW

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

  Probabilità

  Unlikely

  Dimensione

  3

  Many of the the large cornices that formed during the recent storm failed during or just after the storm and some have broken under the weight of a person or snowmobile since the storm. However, many large overhanging cornices still remain perched above wind loaded slopes along exposed ridgelines. While these cornices have become more difficult to break, today's warming will weaken these cornices, and the potential exists for some of them to break on isolated terrain features where they are most overhung and least supported. A great deal of uncertainty exists concerning the strength of these cornices and how far back they may break.

  Identify where cornices exist and stay well back from their edges. Often determining how much a cornice overhangs a slope is difficult, and even when the overhang is visible, they can break behind that point. Giving these large cornices more space than seems necessary represents a wise choice.

• 

  Loose Wet

  N

  NE

  E

  SE

  S

  SW

  W

  NW

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

  Probabilità

  Possible

  Dimensione

  2

  Even though temperatures remained above freezing in some areas last night, the clear skies allowed the snowpack to radiate heat out into the night sky and refreeze. This refreeze will quickly melt away as the strong March sun and warm daytime temperatures heat up the snowpack. The snowpack has not been through enough melt freeze cycles to form good drainage channels to deal with the free water that forms due to the warming or to transition to corn snow conditions. Once the refreeze melts, loose wet snow avalanches in the form of roller balls, pinwheels, and point releases will become possible again today. The sun exposed E-SE-S-SW-W aspects hold the best potential for loose wet avalanches. Most of the loose wet snow instabilities should remain small, but some of them could entrain enough snow to cause problems for backcountry travelers. 

  Use clues like sinking into boot-top deep wet snow and smaller surface wet snow instabilities like roller balls and pinwheels to indicate that enough wet snow exists for problematic loose wet avalanches. These signs indicate that the time has come to move to more frozen slopes, move to less steep slopes, and/or switch activities for the afternoon.