Turnagain Pass and Girdwood

Avalanche problems

• 

  Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  1–2

  Recent Avalanches: There was a human-triggered avalanche on Captain's Chair yesterday, with no one caught or carried, but it happened in steep rocky terrain where the consequences could have been more severe. This avalanche released on a layer of facets underneath the most recent storm snow about 1' deep, which is a very similar setup to the two avalanches from Notch Mountain in Girdwood that were reported over the weekend. 

  Now that we are a few days out from the most recent snowfall and still seeing some avalanches at the interface with the old snow surface, we are transitioning this problem to a persistent slab. There have been a lot of folks out skiing throughout the Turnagain Pass forecast zone with relatively few avalanches reported. So we believe that the setup to produce a persistent avalanche is isolated to specific terrain features where the snow surface before the last storm was still soft enough to harbor near-surface facets. In most places, the prior snow surface was impacted by strong winds to the extent that there were no facets left when the new snow fell. However, in wind-sheltered pockets, there is the potential to trigger an avalanche around 1' deep that could propagate across the terrain and be large enough to bury or injure a person. 

  This is a challenging problem to assess because the distribution is so isolated to these specific wind-sheltered features. So, finding a representative spot to assess the snowpack before entering steeper terrain is going to be tricky. This type of weak-layer setup commonly gives no feedback (collapsing, shooting cracks, etc) before producing an avalanche. You can always use the terrain to reduce your exposure to this type of avalanche by sticking to lower-angle slopes and avoiding terrain traps. Using safe travel techniques can also reduce the exposure of your group by only exposing one skier at a time to steep terrain, always spotting your partners, and grouping up in safe zones outside the runout of overhead avalanche terrain. 

  

• 

  Wind Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  1–2

  Turnagain Pass was spared from the majority of the outflow winds that impacted the surrounding area over the past few days. However, lingering wind slabs up to 1' deep at upper elevations are still on our radar today. These are most likely along ridgelines and convex features that have seen recent wind loading. You can look for shooting cracks on the snow surface and use small test slopes to check how sensitive wind slabs are to the weight of a skier or rider before committing to more exposed terrain.

  In addition, dry loose avalanches are very likely in steep terrain. These shouldn't be large enough to bury a person, but could knock you off balance in steep terrain.