Regions
Kootenay Boundary.
Wind stiffened storm slabs are expected to be problematic at upper elevations Monday. 30 to 50 cm of snow now rests on the mid-February weak layer that may also be sensitive to human triggering.
Weather Forecast
The work week kicks off with a rather disorganized pattern that is not expected to generate any significant snowfall, but a change may be in store as a vigorous low tracks within striking distance of the Kootenay Boundary Wednesday night.MONDAY: A few clouds, freezing level around 800 m, light northwest wind, no significant snowfall expected. TUESDAY: Scattered cloud cover, freezing level around 1000 m, moderate to strong west wind, trace of snow possible.WEDNESDAY: A few clouds in the morning building to overcast in the afternoon, freezing level around 1000 m, potentially strong south/southwest wind, copious amounts of precipitation possible, but the latest model run shows about 15 cm of snow Wednesday night. Stay tuned for more details.
Avalanche Summary
On Friday and Saturday storm slabs were triggered by skiers and explosives at treeline and alpine elevations, 10 to 25 cm deep. Natural and skier-triggered sluffing was also widely reported.
Snowpack Summary
Two successive storms over the weekend produced 10 to 30 cm of new snow accompanied by wind out of the southwest, west and northwest. 30 to 50 cm of snow now rests on the mid-February weak layer that includes facets, surface hoar and a sun crust on solar aspects.Deeper in the snowpack, weak layers that formed in January and December are gradually gaining strength. The layers include several surface hoar and facet layers buried 1 to 2 m below the surface and a crust/ facet interface near the base of the snowpack. No avalanches have been reported on these layers for the past two weeks and snowpack tests are showing improved bonding. Despite these signs, avalanche professionals are still treating these layers with respect and being cautious around shallow start zones and big avalanche paths.
Problems
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.