West Slopes North

Avalanche problems

• 

  Wind Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  1–2

  Two natural slab avalanches were reported in the Baker backcountry at the tail end of the storm 1/18. What was interesting about both of these avalanches is that they propagated widely, much moreso than you would expect from a relatively small storm. The avalanches failed above the MLK crust, which is buried about 1 to 1.5ft deep.  There is uncertainty about whether there may be a persistent layer present above the crust, which would explain why these relatively shallow soft slab avalanches propagated so far. We don't know enough at this time to be able say this is an ongoing concern. Multiple users in the backcountry Thursday mainly reported triggering dry loose avalanches on steep slopes, although one observer did report"very reactive wind-loaded pockets in the morning" which you can read about HERE. 

  On Friday, start on small slopes before you move out to larger terrain. Use test slopes (see video below) and hand pits to check if there are any lingering weaknesses above the crust. Conveniently, the crust is buried shallowly and is obvious, so it should be easy to test the snow above it where our suspect weak layers are. Your largest areas of concern are where wind loading formed slightly stiffer slabs. As is the case with both of the recent avalanches, a likely location for reactive slabs to form is around cliff bands, where thicker drifts can form, or snow piles up deeper. They could also form on leeward slopes just below ridgelines and in gullies like the other slide that was reported which you can see photos of below.

  If you're stepping out onto steeper terrain, make sure you've got an escape route planned if a slope slides. Think twice before stepping onto slopes with high consequence, like ones with trees or rocks below, or ending in an abrupt gully. If you identify any signs of instability, see large wind-loaded features, or have any doubt, avoid slopes steeper than 35 degrees.

  

• 

  Loose Wet

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  1–1.5

  Thursday stayed cool enough that minimal wet loose avalanche activity occurred despite the bright blue skies. There was just enough sun that Friday may start out with a slight crust on steep, sunny slopes. Freezing levels are reaching much higher on Friday, to 3500ft, with minimal wind. As the sun intensifies, you'll probably see indicators on steep, south-facing slopes first, like rollerballs coming down. Snow might get sticky, or gloppy. When this starts happening, pay attention to where you are, and where you're going. You may need to change your plans to avoid steep south-facing slopes, or beneath those slopes as well if wet loose avalanches start running in the new snow layer. The problem may shift a little further to the west as the day progresses. Avalanches will probably stay shallow and in the top few inches, but depending on how much warming we see, they could take up much of the depth of the new snow.