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

  1–2

  New snow during the night and NE winds strong enough to blow snow likely created new slabs of wind-drifted snow on open slopes near ridges. In areas south of Hwy 50 where 4 to 7 inches of new snow fell, larger, more widespread wind slabs will exist. Since wind-loading can multiply the depth of new snow by several times, some of these wind slabs could measure more than a foot or two in depth. North of Hwy 50 where less new snow fell, wind slabs will remain smaller and more limited in distribution. Human-triggered wind slab avalanches will be possible today. Wind slabs will most likely exist in wind-exposed near and above treeline terrain on E-SE-S-SW-W-NW aspects. Sunshine on these slopes later today could make triggering these wind slabs easier.

  Blowing snow, snowdrifts, newly formed cornices (even small ones), scoured slopes, and other wind-created snow surface textures can help identify where wind slabs may exist. Cracks in drifted snow or recent avalanches represent sure signs of unstable wind slabs. The deeper the new snow is the larger the wind slabs could be. If you see signs that wind slabs may exist, move around those areas with extra caution. 

• 

  Loose Wet

  N

  NE

  E

  SE

  S

  SW

  W

  NW

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

  Probabilità

  Possible

  Dimensione

  1–2

  The cooler weather since Sunday night should have allowed some of the wet snow that formed last week to refreeze. Today, temperatures should warm back up into the mid 40's to low 50's, and sunshine should return to the area. These warming factors should allow any new snow that fell last night to become wet. In areas where less new snow fell, today's warming will start to melt the refrozen surfaces that exist. Enough wet snow could form for wet loose avalanches to become possible as the day warms up. Wet loose avalanches entrain more snow as they move, so longer slopes can produce larger avalanches. Terrain traps like gullies, cliffs, and creeks can magnify the consequences of these avalanches in smaller terrain. Wind exposed slopes at the upper elevations may stay cooler due to today's N and NE winds. 

  Signs of unstable wet snow include roller balls, pinwheels, or sinking into boot-top deep wet snow. When the snow starts to get wet, it is time to move off of steep slopes and avoid traveling in areas below steep slopes.