Eastside Region

Avalanche problems

• 

  Loose Wet

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  1–2

  Rain and nearly a week of above-freezing temperatures have left our snowpack wet and messy below and  near treeline in many places. Wet loose avalanches will remain possible today, especially below treeline where another weak and superficial refreeze occurred last night. Wet loose avalanches often start from a single point, like a rollerball or a ski, and fan out as they move downslope. When the snowpack is completely saturated, they can gouge all the way to the ground. In certain circumstances, a wet loose avalanche can be a catalyst for a deeper, wet slab avalanche. This problem is not likely above treeline where temperatures and strong winds will keep the snowpack dry and frozen.

  If the snow is unsupportable to skis or boots and the slope is steep enough to slide, a wet loose avalanche is possible. Consider starting early, seeking out higher trailheads, and avoiding steep slopes below treeline today to minimize your exposure to wet loose avalanches.

  

• 

  Wet Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Unlikely

  Size

  1.5–3

  Prolonged unseasonable weather has allowed water to move through the snowpack over ther the last week. How deep the water has moved depends on a variety of factors, but generally, shallower snowpacks are completely saturated, whereas deep and dense snowpacks are wet only in the top third or so. Wet slab avalanches will remain possible today, particularly at mid and lower elevations where another weak refreeze occurred overnight. Wet slabs can be unpredictable, large, destructive, and can slide on a crust, wet facets, or the ground.

  We have not seen or had a report of a wet slab avalanche in several days, but until we see a hard overnight freeze, uncertainty exists around this problem. Collapsing of a shallow, wet, and weak snowpack was observed as recently as yesterday.  This is a hard problem to manage, and the only certain technique is avoidance of questionable slopes. Consider planning a tour that starts high, and avoid slopes steep enough to slide at lower elevations and where the snowpack is shallow.