Bridgeport Avalanche Center

Lawinenprobleme

• 

  Wind Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Hochgebirge
  • Waldgrenze
  • Unterhalb der Waldgrenze

  Wahrscheinlichkeit

  Likely

  Größe

  1.5–3

  3 days of strong south/southwest winds and 12 iches of SWE has loaded slopes.  Multiple temperature fluctuations during the storm has created heavy wind slabbed snow over lighter less dense layers.   Look for these problematic wind loaded pockets below ridges, in start zones and above specific steeper consequential terrain.   Problem may also exist in isolated pockets (slabs) of steeper treed gullies and chutes.  This layer may also step down the weaker bed surface, talked about in problem 2.  Remember, wind can transport 3-5x the amount of snow fallen onto leeward slopes, creating huge dense and dangerous slabs. 

• 

  Deep Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Hochgebirge
  • Waldgrenze
  • Unterhalb der Waldgrenze

  Wahrscheinlichkeit

  Possible

  Größe

  2–3.5

  Multiple deep snow human triggered avalanches have been reported over the past 3 days since the this past Sierra storm dropped 12" of SWE in a 72 hour period.  This copious amount of snow was accompanied by gale force winds, creating recipe for ultra large leeward wind slabs just below ridgelines.  And these specific zones are/were still holding old rotten sugary snow from October and November storms.  In conclusion, high leeward ridgelines at the Sierra Crest and possibly sub crest ridgeline slopes are holding 15+ feet of dense wind packed wind slabs, sitting on a bed surface of old sugary faceted raincrust.  These are condsidered Deep Persistent Slabs and should be treated with the utmost respect and care.