Seward and Lost Lake

Lawinenprobleme

• 

  Wind Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Hochgebirge
  • Waldgrenze
  • Unterhalb der Waldgrenze

  Wahrscheinlichkeit

  Likely

  Größe

  1–2

  Recent avalanches: Five natural avalanches were observed on Sunday, Feb. 1 northwest of Lost Lake that were small to large in size and likely occurred on Thursday, January 29.

  There is a break between storms today, but there are a variety of new snow problems that could be easy for a person to trigger today in the alpine. We don't have good wind data in Seward, but easterly winds were blowing in the 30s and 40s mph in our other zones yesterday. Above 2,500' where precipitation was falling as snow, fresh wind slabs were forming up to 3' deep. Winds aren't quite as strong today (20s mph expected), but strong enough to continue to form small new wind slabs up to 1' deep. With winds this strong, wind slabs could be anywhere in exposed areas, but especially under ridgelines and on steep rollovers. Keep in mind that triggering a new wind slab could be enough weight to trigger a much larger and more dangerous avalanche described below.

  Storm Slabs: Above 2,500' there is 12 to 18" of new snow in Seward and storm slabs could be found in places sheltered from the wind. There's still a chance a person could trigger one of these avalanches today that should be relatively small, but could still cause problems, especially if it occurs in a place where the snow could pile up or it carries you into rocks or trees. 

  Wet loose: Temperatures are still warm this morning so surfaces may still be wet and wet loose avalanches may still occur. Watch for rollerballs to know a person could trigger one of these avalanches. 

  

• 

  Deep Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Hochgebirge
  • Waldgrenze
  • Unterhalb der Waldgrenze

  Wahrscheinlichkeit

  Possible

  Größe

  2–3

  The storm yesterday added weight to the layer of weak facets that is buried 2 to 5' deep or more. It is becoming more difficult for a person to trigger an avalanche on this layer because it is buried so deep in many places, but it could still happen and the consequences could be serious. The following is what we know about deep slabs:

  • They are triggered where the snow is thinner (near ridgelines or windblown places)
  • They can be triggered remotely (from a flat slope below, on the side or above the avalanche)
  • There can be many tracks on a slope before someone finds the thin spot and triggers the avalanche
  • There is less feedback like whumpfing and shooting cracks
  • They are difficult to assess because normal snowpit tests don't work as well (the layer is too deep)
  • Tests give unreliable results

  This problem can be completely avoided by choosing low angle or simple terrain and staying out from underneath large slopes above.