Central Sierra Nevada

Avalanche problems

• 

  Wind Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  1–2

  Slabs of wind-blown snow have piled up onto the downwind side of ridges, in gullies, and on open wind-exposed slopes. Smaller wind slabs will exist in places where less new snow has fallen. Places south of Emerald Bay, like Echo Summit, Carson Pass, and Ebbetts Pass, which received significantly more snow, will hold larger and more widespread wind slabs. Wind slab avalanches will remain possible today. Some could involve enough snow to bury or injure a person, especially in areas with more snow or where very efficient wind-loading occurs.

  Watch for clues that unstable wind slabs might exist, such as recent avalanches, cracks in the snow, blowing snow, cornices above a slope, drifts or ripples in the snow surface, and other wind-created surface textures. Identifying where unstable wind slabs may exist and skirting around those areas can reduce the chances of triggering a wind slab avalanche.

   

  

• 

  Storm Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  1–2

  Enough new snow has fallen along the Sierra Crest south of Emerald Bay that soft slabs of storm snow may exist on some slopes. Observers reported ball-bearing-like snow (graupel) at the base of this storm snow in the Carson Pass area yesterday. Human-triggered storm slab avalanches may be possible today, especially around Echo Summit, Carson Pass, and Ebbetts Pass, where more snow has accumulated. In places with less new snow, like the northern part of the Sierra Crest and areas east of the crest, loose storm snow could slide down steep slopes. This problem could exist in forested areas people typically consider safe, especially in places with steep slopes and convex rollovers. Watch out for any signs of unstable snow. Recent avalanches, cracking, and test slope failures can indicate a storm slab problem, while small sluffs of loose snow indicate loose snow avalanches may be possible. Sometimes, it is hard to recognize where a storm slab may lurk since the snow surface seems soft and powdery. If you see any signs of unstable snow or have doubts about a slope, go ahead and move to terrain that is not steep enough for snow to slide down.