Regions
Northwest Coastal.
There's DEEP powder and clearing skies in store for the weekend which sounds amazing, but we need to SLOW IT WAY DOWN and stick to conservative terrain as the snowpack adjusts to the recent huge load.
Confidence
Fair - Due to the number of field observations
Weather Forecast
Snowfall should slowly taper overnight. I'm expecting 10 to 40cm out of this last push. Winds should ease back (slightly), but I'm still expecting strong SW winds in the alpine Saturday. No snowfall is expected on Saturday, Sunday or Monday. Looks like it goes clear and dry through at least Tuesday.
Avalanche Summary
I suspect large natural avalanches are running Friday, but we do not have any observations at the moment.
Snowpack Summary
The NW Coast is THE place to be in the province right now. Arctic air has kept things cool and the snow totals are substantial. The storm has produced 50 to 100cm accompanied by screaming winds out of the E through SE. Observations are limited, but there has likely been a lot of slab development in wind exposed terrain at and above treeline. The late-January crust is thought to be down 50 to 150cm in the south of the region and about half this depth in the north. The mid-January rain crust and/or surface hoar layer is down over 150cm in the south and has generally become inactive though it may still be a concern in thinner snowpack areas. The November crust/facet combo near the bottom of the snowpack is thought to be generally well bonded but may still be reactive in the far north of the region.
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.