Summit Lake

Avalanche problems

• 

  Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  2

  This latest round of snow and wind is continuing to add weight to a snowpack with a problematic weak layer of surface hoar buried around a foot deep. While we haven't seen any avalanches on this layer in the Summit Lake zone yet, we are still seeing signs for concern in snowpits. This period of active loading is slowly adding more stress to that weak layer, and this is making it a little more likely that a person will be able to trigger a large avalanche. This layer has caught many people by surprise over the past two months in the Turnagain Pass zone, often producing avalanches without any kind of warning signs, or when there are dozens of tracks on a slope. We still don't trust it, and it is still a major concern.

  There is a lot of uncertainty in how reactive this weak layer is, and the consequences of triggering a large avalanche on that layer are serious. If you are trying to access steep terrain, it will be important to travel carefully. Avoid using slopes with large start zones, or terrian traps like cliffs, gullies, or trees in the runout zone. You can avoid this problem entirely by sticking to lower-angle slopes without any steep terrain overhead.

  Loose Snow Avalanches will become more likely if the sun pokes through the clouds at all today. Be on the lookout for steep solar aspects if the clouds break up at all during the day, especially on slopes with trees or rocks that will heat up quickly.

  Cornice Fall: Cornices have been growing during the active weather over the past week. These can release naturally, and may trigger larger avalanches on slopes below. Limit spending time below cornices, and give them plenty of space if you are travelling along ridgelines.

  

• 

  Glide Cracks

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  2–3

  Glide avalanche activity continues throughout our forecast zones, with fresh glide avalanches seen yesterday on the south side of Tincan at Turnagain Pass, and a new glide crack opening on Fresno. We're in the midst of a very active glide cycle in Girdwood, Turnagain Pass, and Summit Lake, and are seeing very large glide cracks opening up in Seward. These avalanches are large, destructive, and unpredictable. The only way to manage the problem is to avoid spending time under open glide cracks.

  Wet Slab Avalanches: The snowpack has begun its transition to a wet springtime regime. With mostly cloudy skies and slightly cooler temperatures today, we are not expecting to see wet slab activity. However, as John and Mik found at Fresno yesterday, it won't take much more heat before we start to see more wet snow activity in the Summit Lake zone. Be on the lookout for wet snow avalanches in the coming days, especially if the sun comes out and starts breaking down crusts that have formed near the surface.