Seward and Lost Lake

Avalanche problems

• 

  Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Likely

  Size

  2–3

  Recent avalanches: The last known avalanche activity in the Seward and Lost Lake zone was during and immediately after the atmospheric river event, which occurred just over a week ago, from January 16th to 19th. 

  The intensity of the current storm system is expected to ratchet up today, with 4 to 6" of new snow expected in Snug Harbor and 6 to 12" in Seward and Lost Lake. Stronger southeast winds will accompany the heavier snowfall, averaging 20 to 30 mph with gusts up to 45 mph. This gradual accumulation of new snow and wind is likely to be enough to make our weak layer, which is buried 2 to 4' deep, more sensitive to human-triggered avalanches and could cause some natural avalanches in specific areas that receive higher snowfall totals or heavier wind loading. 

  While the likelihood of triggering an avalanche today is on the rise, the advice for how to deal with the problem stays the same. You can use conservative terrain selection to control your risk exposure by sticking to simple, low-angle terrain and avoiding the runout zones of overhead avalanche paths. Remotely triggered avalanches have been especially common on this weak layer, which means you could trigger an avalanche from low-angle terrain onto connected steeper terrain. 

  

• 

  Wind Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Likely

  Size

  1–2

  With yesterday's new snow, combined with another 4-12"  of new snow expected today (0.25 to 1" of water), there will be some soft snow on the surface to be transported into fresh wind slabs. When the winds pick up this afternoon, wind slabs up to 1' deep will be forming on leeward slopes. You can test for wind slabs by using small test slopes to look for shooting cracks or small avalanches in wind-loaded pockets of terrain. These typically form near ridgelines, gullies, and convex rolls where wind-transported snow tends to accumulate. 

  Storm Slabs: In areas like Girdwood, Portage, and Seward, where snow totals are expected to be on the higher side today, there is a chance of triggering an avalanche at the interface of the new snow and the old snow surface, even in sheltered terrain. Using small test slopes or hand pits can be a good way to check how well the new snow is sticking to the old snow surface. This type of avalanche is much smaller than our main concern in problem 1, but it can still get you in trouble if there is a terrain trap involved.