Central Sierra Nevada

Avalanche problems

• 

  Loose Wet

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Likely

  Size

  1–2

  Little to no refreeze likely occurred last night due to increased cloud cover and above-freezing temperatures. Expect to find barely supportable or already wet snow on all aspects this morning. Wet snow avalanches will remain likely today on any slope steep enough for snow to slide downhill. Some of these could be large enough to cause problems for backcountry travelers, especially on long slopes where a wet loose avalanche will entrain more snow as it moves. 

  Signs that the snowpack has become wet enough for wet snow avalanches include pinwheels, rollerballs, sinking into ankle-deep wet snow when you step off your sled or skis, and wet loose avalanches. An early start may not help avoid unstable wet snow today due to the lack of an overnight refreeze, but recreating on slopes less steep than 35 ° without steeper slopes above can reduce the risk of encountering wet snow avalanches. 

  

• 

  Cornices

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Likely

  Size

  1.5–2.5

  The prolonged warm weather and lack of a refreeze means that the cornices along many ridgelines remain weak. Cornice failures will likely continue today. Large to massive blocks falling off these overhanging waves of snow could cause problems on their own or trigger wet snow avalanches on the slopes below.

  Predicting exactly when a cornice will fail is nearly impossible. Cornice failures almost always surprise the people who trigger them by failing farther away from the edge than expected, failing much larger than expected, and failing at an unexpected time. Stay well away from cornices by putting exposed rocks or trees between you and the cornice. Consider avoiding travel on slopes below cornices.