Regions
Northwest Coastal.
Confidence
Fair - Due to limited field observations
Weather Forecast
25 cm to 70 cm expected from 4pm Mon - 4pm Tue.
Avalanche Summary
Control work in the North on Bear Pass on Sunday produced numerous dry loose snow avalanches size 1 -2, 15-30 cm in depth on SW - S aspects. One Xh size 2.5: 50 w x 1200 L x 100-150cm depth. To the South, Shames reported a Na SL sz 3.0, E @1300 m. 250 w x 1700 long. Failing on Nov11-19 SH. Other control work produced results very similar to that in the North.
Snowpack Summary
Saturdays system dumped another 50-75cm in many areas. Sunday brought another 25 - 35cm to upper elevations. The snowpack depth near treeline is already around 300cm. Fluctuating freezing levels and varying precipitation intensity and wind throughout the recent storms has probably resulted in various weaknesses within upper snowpack. A buried surface hoar layer may be found down close to 100/150cm, but there is no recent information on the presence and sensitivity of this layer. The mid and lower snowpack is generally well settled/strong with an old rain crust near the ground.
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.