Central Sierra Nevada

Problèmes avalancheux

• 

  Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpin
  • Limite forestière
  • Sous la limite forestière

  Probabilité

  Possible

  Taille

  2–2.5

  Multiple weak layers exist in the snowpack under the recent Sunday storm snow.  These layers of concern exist in near and below treeline areas on NW-N-NE aspects.  The layer of buried surface hoar and near surface facets are showing signs of gaining strength and adjusting to the new storm snow load with signs of instability decreasing.  With that said, unlike typical storm slab issues, these layers will take longer to adjust and gain strength.  These weak layers vary widely throughout the forecast region in weakness and location.  Human triggered avalanches large enough to bury or injure a backcountry user remain possible.

  Look for signs of instability while traveling in the backcountry:  recent avalanche activity, shooting cracks, whumpfing, or collapsing would all be signs of an active weak layer in your area.  Remote triggering and wide propagation are also possible with persistent slab avalanche problems.  Utilize good terrain management strategies with your group to limit or avoid your exposure to this avalanche problem.  

• 

  Loose Wet

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpin
  • Limite forestière
  • Sous la limite forestière

  Probabilité

  Possible

  Taille

  1–2

  Snow surfaces became wet yesterday in the late morning with widespread roller balls on E-SE-S-SW-W aspects.  Warmer temperatures forecasted for today with decreased winds will further wet loose instabilities.  Many of these issues will be in the form of roller balls and pinwheels with larger wet loose avalanches that involve more snow becoming possible.  Some of these instabilities could also spread over to the northerly aspects depending on the warming in your area. 

  Once the snow surface becomes wet, heavy, and/or sticky, it is time to move off of and away from any steep avalanche terrain.  Snow surface conditions in these areas could have thin surface crusts in the morning turning into wet heavy snow as rapid warming occurs.