West Slopes North

Avalanche problems

• 

  Wind Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Likely

  Size

  1–2

  Natural and human-triggered avalanches were reported on Thursday, many of which occurred on wind-loaded features, which you can read about in THIS observation from a forecaster who was in the Baker backcountry on Thursday.  Most of the avalanches were triggered in areas where snow was actively loading onto a slope, forming new drifts. Some drifts were shallow and soft, whereas others were larger. 

  We'll have a break in the multi-day storm on Friday, but given the recent loading event, you can still expect to trigger small and large avalanches in recently drifted snow. Search for thicker-feeling snow beneath you, and identify smooth, pillowlike surfaces or textured-looking snow. You may see clues like long shooting cracks as additional indicators of pent up energy in new slabs. Avoid areas where you identify these wind slabs on steep slopes. 

  

• 

  Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  2–3

  A thin layer of surface hoar was buried on March 8, and several spooky and alarming avalanches subsequently occurred on this layer, which is now averaging about 2 feet below the snow surface. That surface hoar, and another layer of facets buried a few inches deeper, exist just above the March 4 crust, which is easily identifiable in the snowpack as the obvious uppermost crust you'll find.

  Canyon Creek was the first location where the problem was reported, resulting in small and large avalanches, some of which were remotely triggered, earlier in the week. One avalanche was remotely triggered in the Baker backcountry on Thursday, propagating far, wrapping around features, and reportedly failing just above the crust. Without further investigation, surface hoar or facets may have been the culprit in this avalanche due to failure depth. Other avalanches in the area on Thursday may have also failed on the persistent layer.

  Another observer at the Twin Sisters found even more persistent weak layers, intentionally and remotely triggering several avalanches that surprised them, propagating further than expected. This area tends to have weaker, shallower layers, which may not be representative of most locations in the zone. 

  Given the recent smattering of persistent slab avalanches, we believe the avalanche problem is alive and well, albeit more active in some areas of the zone than others. To avoid this problem, which could likely result in large, unsurvivable avalanches, avoid steep terrain in northwest through east-facing slopes at middle and upper elevations, especially where terrain traps exist below you. 

  

• 

  Loose Wet

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  1

  The sun will break through clouds for at least part of the day, and you can expect rollerballs and small wet loose avalanches on steep slopes that are directly facing the sun. The largest amounts of activity will occur where light, fluffy surface snow layers exist.

  Avalanches or rollerballs will first initiate where snow falls off trees, or near rocky outcroppings. They may pick up mass as they roll or slide downhill. If you notice this activity, or feel the snow surface getting wet and heavy, steer around steep slopes facing into the sun. Shift to lower angle terrain away from where avalanches on those steep slopes will run, or onto shadier aspects.