Seward and Lost Lake

Avalanche problems

• 

  Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  2–3

  Recent Avalanches: There was a fatal avalanche accident on the back side of Seattle Ridge in Warmup Bowl on Saturday in which the rider was caught and buried, and did not survive. We have seen wet loose avalanches releasing on southerly facing slopes around Seward. This includes a wet loose avalanche on Lowell Point that ran almost to sea level on a south facing slope. Earlier last week there was an avalanche on the south side Mt Marathon that deposited 10’ of debris in Lowell Canyon.

  It has been over two weeks since the last known avalanches have occurred on the layer of buried surface hoar that we are concerned with. This seems to indicate that the layer is becoming less reactive in the Seward zone than it is in the Turnagain Pass  area, but there is a lot of uncertainty in that. This layer has proven to give unreliable feedback, producing avalanches even when there are multiple tracks on a slope or when nearby snowpits seem to indicate a stable snowpack. If you are traveling in the Seward or Lost Lake area today, keep this high uncertainty in mind and reduce your risk exposure by avoiding terrain with higher consequences if you were to trigger an avalanche. This includes slopes with terrain traps like gullies, cliffs, or trees in the runout zone, or large connected slopes that could produce very large avalanches. 

  We've been finding the most concerning structure at elevations between roughly 1500' and 3000'. Sometimes this problem will give warning signs like shooting cracks or collapsing, but that won't always be the case. You can avoid this problem entirely by staying  off of steep slopes, and avoiding low-angle terrain connected to steeper slopes overhead. If you do decide to get into steeper terrain, be aware that this layer has proven to be very challenging to assess and has caught many people by surprise in recent weeks.

  

• 

  Wind Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  1–2

  Yesterday's east winds have already started to back down, and should remain light today. However, they were blowing strong enough to move snow for the past 24 hours and some of those most recent wind slabs may remain reactive today. These will be around a foot deep, and are most likely to be found in upper elevations on steep slopes below ridgelines, convex rolls, and steep gullies. You may see signs like shooting cracks or collapsing, or it may be more subtle clues like stiffer snow sitting above softer snow. These relatively smaller avalanches will be big enough to be a concern on their own, but also have the potential to step down to a much larger avalanche described in Problem 1 above.

  Loose Snow Avalanches: Skiers yesterday reported widespread rollerball activity on steeper slopes, indicating the snow on the surface is becoming warm in the heat of the day. Be on the lookout for loose snow avalanches if the sun pokes through the clouds even for a short while. These often release near trees or rocks, or below cornices. They can be particularly dangerous on longer slopes where they can entrain more snow, or if they run into terrain traps like gullies or cliffs.

  Glide Avalanches: We're continuing to see glide avalanche activity across the advisory area. There is currently a very large glide crack on Mt. Marathon, which may release at any time, or may slowly creep open and never release. These avalanches are very large and unpredictable. The best way to manage this problem is to avoid spending time under open glide cracks.