Regions
Northwest Coastal.
A wallop of snowfall is expected Thursday night with the most in the south of the region. All the recent storm snow will likely be touchy to human traffic on Friday. Conservative route-selection is recommended.
Confidence
Moderate - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
THURSDAY NIGHT: Cloudy with snowfall, accumulation 10 to 20 cm, moderate southwest winds, freezing level 500 m.FRIDAY: Cloudy with snowfall, accumulation 5 to 10 cm, moderate southwest winds, alpine temperature -6 C, freezing level below valley bottom.SATURDAY: Cloudy with light snowfall and afternoon clearing, accumulation trace to 5 cm, light north winds, alpine temperature -20 C, freezing level below valley bottom.SUNDAY: Clear skies, strong northeast winds, alpine temperature -25 C, freezing level below valley bottom.
Avalanche Summary
On Wednesday, a few small pockets were reactive to skier traffic, with slabs up to 15 cm deep. The likelihood of triggering avalanches will increase into Friday with the plethora of new storm snow.
Snowpack Summary
About 20 cm of snow has fallen in the south of the region and another 20 cm or so is expected by Friday midday. In the high alpine, it fell on a wind-affected surface, such as scoured snow on windward slopes and thicker snow deposits in lee terrain features. The snow fell on a thick melt-freeze crust below around 1600 m. Expect the snow to be reactive to human traffic on Friday.In the south of the region, the remainder of the snowpack is generally well-settled.Around Bear Pass and in the north of the region, there is a weak layer of feathery surface hoar crystals about 50 cm deep. This weak layer is likely most prominent in sheltered and shaded areas. Also in the north, a few weak layers may still exist within the middle and lower half of the snowpack. These include another layer of surface hoar around 70 to 100 cm deep and a weak layer of sugary faceted snow around 200 cm deep.
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.