Blues

Avalanche problems

• 

  Wind Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Likely

  Size

  1–2

  So far this morning the Elkhorns and Blues have received 8"-10" of new snow overnight depending on location. Another 2"-4" of snow is in the forecast for today. This snow was accompanied by light to moderate west winds. Expect to find fresh and thick windslabs on northeast, east, and north facing terrain. Suspect the formation of touchy windslabs on any steep leeward terrain you are considering ! This new dump of new snow rests upon a 4" thick layer of light snow and (now buried) surface hoar, which makes for an ideal weak layer. Below this ideal weak layer there is a 1"-1.5" stout rain crust which makes for an ideal sliding surface. This ideal avalanche layer cake I just described will make for dangerous avalanche conditions today on terrain steeper than 30 degrees. Human triggered avalanches are likely on steep terrain where windslabs have formed. Windslabs appear like smooth rounded domes or large pillows. When traveling on a windslab the snow can sound hollow or drumlike. The snow can feel thick or dense as well. Other windslab red flags include the observance of shooting cracks in front of skis or boards. The most obvious red flag is the observance of avalanche activity of any kind in the area you are traveling through. It is recommended that you avoid avalanche terrain with recent wind deposits today. Continually test the snow you are traveling through today and monitor slope angles.

  

• 

  Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  1–2

  While ski touring in the Blues yesterday I dug a snowpit on a northwest facing slope at 5244' . Down about 14" I found a layer of buried surface hoar. This persistent weak layer was mostly unreactive to stability tests I performed. The Extended Column Test I performed failed using a moderate amount of force, no propagation was observed. This layer did not fail while performing a compression test. That said, this persistent weak layer will get tested with todays 10"-12" dump of new snow. If you hear whumpfs in the snow you are traveling upon today, that is a red flag that the snow is unstable and could avalanche on terrain steeper than 30 degrees. Persistent slab avalanches can be triggered remotely from below or to the side of avalanche paths. If you see any of the aforementioned red flags, consider recreating on slopes less than 30 degrees today.

• 

  Deep Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Unlikely

  Size

  1–3

  We have been discussing the deep persistent slab problem in the snowpack all season and that struural snowpack problem still exists. My Snowpit data from my travels in the Blues yesterday revealed thick layer of facets at the ground that the entire snowpack rests upon. This layer continues to gain strength but still lurks in the basement. It is very unlikely that an avalanche could be triggered on this layer but still possible. Low probability of triggering a deep persistent slab avalanche but very consequential if you trigger one of these potentially unsurvivable monsters.