Central Cascades

Avalanche problems

• 

  Wind Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Likely

  Size

  1–2

  With 6-11" of new snow and strong west winds, human triggered avalanches will be likely on north, northeast, east, southeast and south aspects near and above treeline. With strong to extreme winds, we could see wind loading patterns in unusual places such as lower down on slopes. 

  When traveling in the mountains, look for signs of wind slabs such as wind drifting snow, areas below cornices, pillow like features, and textured snow. Seeing recent avalanches and cracking will be a clear sign of instability. Ease into the terrain, and look for safe test slopes to stomp on if considering larger terrain. Consider conservative decision making while traveling, and if in doubt stick to slopes lower than 30 degrees. Wind slabs are usually most reactive during and immediatly after storms. Lastly, remember that wind can deposit snow 3-5x deeper.

  

• 

  Storm Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  1–1.5

  With heavy snow fall we could see storm slabs form near and below treeline. I suspect these slabs will be on the smaller side. Be on the look out for storm slabs especially above terrain traps such trees, cliffs, gulleys, creeks, etc.

  Storm slabs are more likely triggered in steep and unsupported slopes. If you see signs of instability such as recent avalanches and/or cracking, stick to lower angle terrain.

• 

  Cornices

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  1–1.5

  I suspect cornices will be growing on ridglines with new snow and strong winds. With low visability likely, be cautious of conrices on ridgelines and give them a wide distance. Remember that cornices can break farther back than expected.