Seward and Lost Lake

Avalanche problems

• 

  Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Very Likely

  Size

  2–3

  Recent avalanches: We received secondhand reports of multiple human-triggered avalanches in the Lost Lake area, some of which were very large, and at least one where someone rode off of a moving slab. We also documented widespread natural avalanche activity from Moose Pass to Seward, with wide-propagating avalanches running to valley bottoms.

  This weekend has us on edge. We're on the heels of a major loading event on top of a problematic snowpack, we just witnessed a very impressive natural cycle, and people have already triggered very large avalanches from flat terrain. All of this is a recipe for an avalanche accident, and we are urging everyone to recognize the severity of the current conditions. Travel in and below avalanche terrain is not recommended today.

  Conditions are touchy right now due to the magnitude of the recent storm combined with poor snowpack structure beneath the new snow. Seward and Lost Lake recorded 2 to 3' snow, equalling 3.1" snow water equivalent (SWE). This came in with extreme easterly winds, which briefly changed directions yesterday afternoon, effectively loading all aspects within the past 24 hours. All of this new and windblown snow is adding a lot of weight to a weak layer of advanced facets, now buried 2 to 4' deep or deeper. The layer was very reactive ahead of this storm and has now been pushed to its breaking point. Based on the human-triggered avalanches yesterday, we are seeing clear signs that this layer is seriously concerning.

  The only way to manage this problem is to avoid traveling on or below steep slopes.  This is not a typical storm snow issue that will improve in a day or two—it will take time to heal.

• 

  Storm Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Very Likely

  Size

  1.5–2.5

  The new and windblown snow from the past three days is expected to remain reactive today. Though it will likely be slightly more stubborn than it was yesterday, it is still likely a person will be able to trigger a big avalanche, even if it doesn't impact the deeper weak layers discussed in Problem 1 above. This storm came in warm and wet, dropping 2 to 4' of heavy snow on top of the dry, low-density surface that existed before the storm.

  Winds have remained strong since it stopped snowing, and there is likely a fresh round of touchy wind slabs that have formed. These may have formed further downslope than we often see, which is another out-of-the-ordinary pattern making conditions unusually dangerous today. While this adds complexity to the avalanche equation, the terrain management is simple: avoid traveling in avalanche terrain for now.

  Upper elevation estimated storm totals since Wednesday night are listed below:

     Snowfall   Snow Water Equivalent (SWE)  Girdwood  3-4'  3.8  Portage  2-4'  3.8  Turnagain  1.5-2'  1.6  Summit  1.5'  1.7  Seward  2-3'  3.1