Central Sierra Nevada

Avalanche problems

• 

  Loose Wet

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  1–2

  More sun and warmer daytime temperatures than yesterday will allow wet loose avalanches to become possible again today. The lack of strong NE winds to balance out the warming means that wet snow could be more widespread. Long, steep, sunny slopes could produce wet loose avalanches large enough to cause problems for people, and terrain traps like gullies or cliffs can magnify the consequences of any avalanche. 

  Roller balls, pinwheels, and sinking into boot-top deep wet snow can indicate that enough wet snow exists for wet loose avalanches to occur. Moving to a different aspect where the snow remains colder or recreating on lower angle slopes without steep sunny slopes above can help reduce exposure to wet loose avalanches.

  

• 

  Wind Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  1–2

  While triggering a wind slab avalanche should become more difficult as the wind-blown snow bonds to the snow below it, these avalanches may remain possible today. Most wind slabs will exist in areas near and above treeline where wind-blown snow has piled up on the downwind side of exposed terrain features like ridges, gullies, and open slopes. An isolated wind slab may even still linger in below treeline terrain due to the strength of the winds. These stiff wind slabs often break after someone gets onto the slab and has already committed to a slope. Today's strong sunshine could make triggering one of these wind slabs easier on sunny slopes.

  Recent avalanches, snow surface cracking, blowing snow, newly formed cornices, piles of drifted snow, and snow surface texture can all help identify where unstable wind slabs may exist. Traveling in areas sheltered from the wind can reduce the chance of triggering a wind slab and increase your chances of finding softer, less variable snow.

  

• 

  Cornices

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  1–2

  Sun and warm weather will weaken the cornices that exist along many ridgelines. These cornices could break far away from their edges, causing people to take long falls while getting pummeled by large pieces of falling cornices. In some places, the NE winds have scoured material away from the cornices; in others, they remain large and overhung. A high degree of uncertainty exists about exactly which cornices will fail and when they will fail. 

  Cornice collapses often surprise people. They fail farther back from the edge than expected and break wider than expected. If your route takes you along a corniced ridge, keep exposed rocks or trees between you and the cornice edge. Also, be wary of traveling on slopes under cornices. It's best to avoid those slopes when cornices could fail, but if you have to travel on them, spend as little time as possible doing so.