Regions
Northwest Coastal.
Wind slabs will likely be found at upper elevations and may be reactive to human triggering, especially in lee features.
Confidence
Moderate - Due to the number of field observations
Weather Forecast
MONDAY NIGHT: Cloudy with isolated flurries, trace accumulation. Light west-south west wind. Freezing level 400 m.TUESDAY: Cloudy with isolated flurries, up to 5 cm accumulation. Moderate south-south east wind. Freezing level 500 m.WEDNESDAY: Flurries, 5-20 cm. Moderate south wind. Freezing level 600 m.THURSDAY: Flurries, 5-10 cm. Light to moderate south-south west wind. Freezing level 700 m.
Avalanche Summary
On Sunday, explosives were able to trigger wind slab avalanches to size 1.5. Additionally, a large (size 2) natural wind slab avalanche was observed on a northeast aspect.Several small natural and explosives triggered avalanches (size 1-1.5) were reported in the region on Friday.
Snowpack Summary
10-30 cm of new snow sits on a melt-freeze crust to approximately 1000 m. Above 1000 m this new snow is just adding to the 150+ cm of snow that has fallen over the past week. Moderate to strong winds have redistributed recent snow and likely formed wind slabs at upper elevations, especially in lee features. Expect to find more reactive slabs in wind loaded areas, and especially in places that received high snowfall amounts over the weekend.120-200 cm of snow sits on a weak layer that was a concern when the first waves of the storm hit the coast, but the strength of this layer has generally improved over the past week. This layer consists of surface hoar (feathery crystals), facets (sugary snow), and crusts that formed during the dry spell in early December. The surface hoar is most prevalent and has most recently been reactive between 1100-1300 m in more northern portions of the region, and is something to keep in mind if you plan to travel to areas like Ningunsaw.Deeper in the snowpack, there are several crusts, including an early season crust with facets near the bottom of the snowpack.
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.