Regions
South Coast Inland.
Snowfall amounts over the coming days vary between the north and south portions of the region. Light to moderate amounts of snow accompanied by wind gradually raise danger ratings.
Confidence
Moderate - Forecast snowfall amounts are uncertain on Wednesday
Weather Forecast
WEDNESDAY: Flurries, accumulation 10-15cm / Moderate south wind / Alpine temperature 0 / Freezing level 1400mTHURSDAY: Flurries, accumulation 5-10cm / Moderate to strong south wind / Alpine temperature -1 / Freezing level 1300mFRIDAY: Snow, accumulation 15-30cm / Moderate south wind / Alpine temperature -1 / Freezing level 1200m
Avalanche Summary
There is no recent avalanche activity to report. On Wednesday, wind slabs may remain reactive in human triggers at upper elevations. In northern parts of the region, the deeper February weak layers continue to present a low probability / high consequence scenario.
Snowpack Summary
Expect another 10-15cm of snow at upper elevations to add to the storm snow amounts from last weekend which totalled roughly 40 cm around Coquihalla and Allison Pass and 30 cm around Duffey Lakes. Freezing levels reached roughly 1400 m at that time, resulting in rain and/or wet snow at lower elevations. Thicker wind slabs and large cornices likely exist in alpine terrain. The storm snow sits above a widespread rain crust up to about 2100 m, but the snow has likely formed a good bond to this crust. In the north of the region, the February weak layers are 80-120 cm deep and include a buried surface hoar layer that recently produced a few persistent slab avalanches and a crust/facet layer that appears to be gaining strength. In the southern parts of the region, the lower snowpack is generally stable.
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.
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.