Elkhorns

Avalanche problems

• 

  Wind Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  1–2

  The recent Wednesday evening storm that brought us 4"-8" of new snow was accompanied by moderate winds from a variety of directions. Reactive windslabs have been observed in the Wallowas and Northern Elkhorns by myself and other observers. These reactive windslabs have been observed near ridgelines on west, northwest, northeast, and east facing aspects. I expect it would be possible to trigger a windslab avalanche today on steep wind affected terrain near ridgelines.

  

• 

  Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  1–2

  We continue to see buried surface hoar in the upper half of our snowpack throughout the Wallowa and Elkhorn mountains. It is showing up in our snowpits as a faint 1"gray line that can sometimes be difficult to see. We are seeing this buried surface hoar at and below treeline on all aspects. That said, I dug a snowpit yesterday in the Northern Elkhorns and found this buried surface hoar buried 1.5' down from the snow surface near a ridgeline at 8400' on a north facing slope. These layers of buried surface hoar in our snowpack continue to be reactive in stability tests. A natural avalanche in the Fish Lake area was recently observed that failed on buried surface hoar as well. Buried surface hoar is a nasty weak layer that is the culprit in a lot of avalanche fatalities. It can be hard to locate and it persists in the snowpack for a long time. Where buried surface hoar is present, avalanches can be triggered remotely from below or to the side of slopes. Also, avalanches that fail on buried surface hoar can be larger than you might expect. For now it is recommended riders stay off of and out from under terrain steeper than 35 degrees. As always, one rider at a time while traveling upon or near steep terrain. If any red flags are observed (whumpfing, shooting cracks, collapsing), it is time to back off that steep slope and head for low angle terrain less than 30 degrees steep where you will find a ton of good riding opportunities.

  

• 

  Deep Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Unlikely

  Size

  1–3

  We are still observing facets deeply buried in our snowpack near the ground and around crust layers that are buried near the ground. While touring in the Northern Elkhorns yesterday I found these deeply buried weak layers in snowpits above and below treeline. Although these deeply buried faceted weak layers are slowly gaining strength, they are still failing in snowpack stability tests. Deeply buried basal facets and crust facet combinations have produced  large and consequential avalanches in our forecast area in the past so we continue to diligently monitor these deeply buried weak layers. The likelihood of triggering one of these dangerous beasts is low but the consequences of doing so would be severe. This type of avalanche can be triggered on steep slopes where the snowpack is thin. The best way to manage the risk is to stay off of and out from under slopes steeper than 35 degrees,especially near shallow rocky areas.