Turnagain Pass and Girdwood

Avalanche problems

• 

  Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  2–3

  Our primary concern continues to be a layer of buried surface hoar about 1 to 3' deep that has been plaguing our snowpack for the past six weeks. Human-triggered avalanches are still possible on this layer, with the potential to cause very large avalanches that can be triggered on relatively low-angle slopes. To avoid this issue you can stick to low-angle terrain and avoid traveling underneath steeper slopes overhead. 

  As the snowpack starts to transition to a spring pattern, a firm melt-freeze crust has been forming on the surface up to about 2000', and even higher on solar aspects (east, south, west). When frozen, this icy layer adds a lot of strength to the snowpack and should decrease the likelihood of triggering an avalanche on a deeper weak layer. However, in the afternoon as the crust layer starts to lose strength and turn into melted snow the likelihood of being able to trigger an avalanche will increase dramatically. 

  If you decide to venture into steeper terrain you can hedge your bets by avoiding slopes with terrain traps below like gullies, creeks, trees, or abrupt transitions from steep to flat terrain. Any of these features can increase the burial depth or consequences in case of an avalanche. Most human-triggered avalanches on this weak layer have been in the Seattle Creek and Lynx Creek drainages. However, recent observations from Cornbicuit and Pete's North have shown that the layer exists and is still concerning on the skier's side of the road. Heads up, seeking out sheltered dry snow on northerly aspects could be a likely place to find a problematic slope for this weak layer. 

  

• 

  Glide Cracks

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  2–3

  A new cycle of glide avalanches started last week throughout the Turangain Pass and Summit Lake forecast areas. These seem to be releasing mostly on solar aspects at mid and lower elevations. These large and destructive avalanches are unpredictable and the best way to manage them is to avoid traveling underneath slopes with glide cracks. 

  Wet Loose Avalanches have been releasing naturally and will be easy to trigger on sunny slopes (east, south, west) as temperatures warm up in the afternoon. Wet loose avalanches are typically small but can be concerning in steep terrain or if they run far down a slope and entrain a lot of wet snow on the surface. Summer trails located underneath large sunny slopes can be impacted by wet loose avalanches running into lower elevations. 

  Cornices naturally start to shed off ridgelines in the spring and can be surprisingly large when they fail. Try to avoid traveling underneath large cornices getting direct sun and give them a wide berth when traveling along ridgelines. 

  Wind slabs might also be forming today at upper elevations where loose snow remains on the surface. Northwest winds will be strongest in typical gap wind areas, like along Turnagain Arm and near Seward. Keep an eye out for active wind transport along ridgelines as a sign that wind slabs are forming. Shooting cracks and hollow-feeling pillows of snow are additional signs to help identify wind slabs.