Regions
Northwest Coastal.
Confidence
Poor - Due to limited field observations for the entire period
Weather Forecast
The weather pattern continues with generally cloudy skies, light amounts of precipitation, light winds and cool air. The arctic air mass that has been stationary over the Northern part of the province will slowly start to retreat Sunday afternoon bringing temperatures back to seasonal norms, and the strong outflows will diminish. Saturday: FLVL’s 200 m, snow amounts 5 cm, ridgetop winds SE 20 km/hr, alpine temps near -8.Sunday: FLVL’s 400m, snow amounts 5-10 cm, ridgetop winds SE 15 km/hr, and alpine temps - 7.Monday: FLVL’s surface, ridgetop winds SE 15 km/hr, alpine temps -10.
Avalanche Summary
On Thursday: a report of a skier triggered size 1.0 occurred on a E-SE aspect @ 1180 m, down 10-40 cm and 15 m wide, on a convex cross-loaded terrain feature. Explosive control performed in the region also triggered several size 1.0-1.5 slab avalanches, 25 cm deep, 30 m wide.
Snowpack Summary
New storm slabs and wind slabs instabilities exist at treeline and alpine locations. They may be touchy to rider triggers; especially on leeward slopes and behind terrain features where pockets of wind slab easily build. A couple recent test results done in the upper storm snow show an easy (RP) shear down 20-25 cm and a hard (RP) down 80 cm. The mid-pack is generally gaining strength and well settled. Digging down deeper is the early November facet/crust layer. This crust sits near the base of the snowpack, and recent tests done in the Bear Pass area around 1100 m have proved this layer to be unreactive. Testing done in the Shames area on this interface also showed no results, with moist snow below.Total snowpack depth is probably around 150-180 cm at treeline, and deeper but more variable in the alpine. The snowpack at below treeline elevations is reported to be strong.
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.
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.