East Slopes North

Avalanche problems

• 

  Wind Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  1–2

  Northeast winds could be strong enough to transport snow in the northern part of the zone, especially near Harts Pass. Westerly wind formed older wind slabs from Saturday night to Sunday, as a storm delivered about 10 inches of snow at the Cascade crest. Pay attention as you move into wind-exposed terrain higher in the mountains. Note any signs of wind drifting and anticipate which slopes hold wind-drifted slabs.

  You can use visual clues such as cornices, blowing snow, or wind textured surfaces to identify wind-affected terrain. You can easily dig down to the Valentine's Day crust with your hand, ski pole, or probe to look at recent snow and wind slab depths. Watch for signs of unstable snow, such as shooting cracks. If you find deep drifts of snow or see cracks shooting out in front of your skis, steer around steep slopes. On steep, wind-sheltered slopes, you may be able to trigger loose avalanches in the recent storm snow.

  

• 

  Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  2

  Snowpack tests have indicated that large persistent slab avalanches are still possible on shaded slopes above 5,000ft. Recent snow and wind have added a slight load these weak layers. Persistent slab problems can be tricky and become more sensitive after additional loading. A shallow wind slab could step down, resulting in a larger and surprising avalanche. Consider avoiding shallow, rocky, or very steep unsupported slopes on northern aspects where this snowpack structure likely exists.

  Indicators of persistent slabs are whumphing collapses and snowpack tests that pop or drop suddenly. While it's been at least 10 days since the last reported persistent slab avalanche, observers continue to report these signs of instability. You can dig and find the late-January weak layer about 2 feet below the surface. This layer is a combination of weak sugar-like facets sandwiched between two crusts in many areas. Sometimes you'll find weaker snow or old surface hoar above the upper crust. The weak layers are deepest near and west of the Cascade crest and in wind deposited areas. The crusts may be found near the surface in the eastern part of the zone and in wind-scoured areas.