Galena Summit & Eastern Mtns

Avalanche problems

• 

  Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  1–2

  Multiple human-triggered avalanches have occurred in the past 5 days. All involved layers of weak snow in the upper snowpack. On Friday in the Baker Creek drainage, riders triggered three avalanches on wind-loaded slopes—one was remotely triggered from the ridgeline above (photo, photo). I looked at these slides on Saturday and found that they failed 10-16" down on a layer of well-developed facets that formed during the mid-winter drought. A different weak layer—facets on a crust—was responsible for a  skier-triggered slide on Wednesday near the head of Smiley Creek. These slides are clear indicators triggering an avalanche involving this weak snow is possible.

  This zone has received less recent snowfall than further north, and you generally need added loading from wind to have a slab. Signs of past wind loading may be masked by more recent snowfall. The combination of weak layer + slab is not widespread, but where it exists it is possible to trigger an avalanche large enough to bury you. Moderate to strong winds over the past weeks have affected the snow in both middle and upper elevation terrain.  You can significantly reduce your risk of triggering a slide involving these layers on slopes that are less than 35 degrees that are sheltered from the effects of the wind.

  ADDITIONAL DISCUSSION: 1-2" of snow fell in this Zone on Saturday night. Winds blowing out of the NW transported this new snow into small, isolated drifts that may continue to be reactive to your weight today. While small, they may be large enough to knock you off your feet, which can have higher consequences in steep, rocky terrain. Importantly, these slabs are adding weight to the buried persistent weak layers described above.