New snow accompanied by strong winds will require a conservative approach to terrain. Gather observations as you travel.
Weather Forecast
As the Pacific frontal system tracks east the Interior regions will experience unsettled conditions bringing new snow and strong winds overnight and into Saturday. An arctic front will push its way towards the BC North Coast on Sunday, moving cold air from North to South. Saturday: Freezing levels near 1000 m with alpine temps near -4. Snow amounts 5-10 cm and ridgetop winds light from the SW.Sunday: Freezing levels at valley bottom with alpine temps near -10. Flurries expected and ridgetop winds light from the West with strong gusts.Monday: Mix of sun and cloud with freezing levels in the valley bottom and alpine temps near -15.
Avalanche Summary
On Thursday, explosives control produced numerous slab avalanches up to size 2.5 on SE aspects between 1900-2100 m. These avalanches were on average 30 cm deep, running deeper up to 1 metre on fans below cliffs. The largest (size 2.5) was estimated 150 m wide and running 400 m in length.
Snowpack Summary
New snow and strong winds will likely build new storm slabs and wind slabs on open leeward slopes and behind terrain features. Early season snowpack observations are still very limited but the threshold for avalanches has been exceeded at treeline and in the alpine. Reports suggest that the snow depth at treeline is typically 110-150 cm but a report from the east side of region shows only 80 cm at treeline. The snowpack tapers off drastically below treeline and below 1700 m there is not yet enough snow for avalanches. Limited reports suggest the crust from the middle of November is down 50-80 cm and the crust from early November is down 80-110 cm.
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.