Seward and Lost Lake

Avalanche problems

• 

  Deep Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Unlikely

  Size

  2–3

  Recent Avalanches: On Friday, a small wind slab was triggered by a snowmachiner at 2,500' on a southeast facing slope in the Snug area. Natural avalanches probably occurred during the wind event, but we haven't been there or received reports.

  There were two large natural avalanches in Girdwood last week that likely failed on weak snow near the ground. These avalanches occurred on the north side of the valley that has less snow than the south side of the valley. There are places in the Seward zone that have a thin snowpack where this could occur, although we think it is unlikely. The most likely places are above 3,000' close to scoured ridgelines or other places that have been stripped of snow. If a person were to find one of these spots the avalanche could be very large.

  The person that triggered the avalanche in Ragged Bowl on Thursday described seeing shooting cracks and triggered a whumpf in a windblown area at the saddle of Raggedtop Bowl. Noticing these red flags along with active wind transport they decided to choose a slope that looked less wind loaded. They also described choosing the slope they skied based on the lack of terrain traps and a good runout. These are good ways to reduce your chances of a serious outcome if you get surprised. 

  Loose Snow Avalanches: The loose snow avalanches reported yesterday were small, but they can grow larger as they entrain snow on their way down. It's important to escape these as soon as possible to avoid getting carried over a cliff or into trees.

  Cornices tend to fail with warming temperatures, which should be the case today. Avoid spending time underneath cornices and give them space on the ridge as they tend to break back further than expected.

  

• 

  Wind Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Unlikely

  Size

  1–2

  Surface conditions probably look like the moon at this point after 4 days of relentless wind. There was very little snow being blown off the ridgelines yesterday, not because there was less wind, but because there is not much snow left to move around.

  In Seward, the rain crust from the storm in early February reaches higher elevations than our other forecast zones. Weak snow can develop around crusts, which can make wind slabs sensitive to a human-trigger for longer than the normal 1 or 2 days. We don't know how high this crust exists in Seward, but there's a chance a person could still find a wind slab above 2,500' in places that have had wind loading over the last week or so. The most likely place to find this is in a cross-loaded gully or on a steep roll. Wind slabs feel firm and may sound hollow.