Regions
Kootenay Boundary.
Wind slabs linger in lee features at higher elevations. Watch for signs of avalanche activity and locally unstable snow, such as whumpfing and shooting cracks.
Confidence
Moderate - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
FRIDAY: Increasing cloudiness with snowfall beginning late afternoon, accumulation 2 to 5 cm, moderate to strong southwesterly winds, alpine temperature -14 C, freezing level below valley bottom.SATURDAY: Early-morning snowfall then clearing to partly cloudy, accumulation 5 cm, light to moderate northwesterly winds, alpine temperature -11 C, freezing level near 500 m.SUNDAY: Cloudy with light snowfall, accumulation 5 to 15 cm, moderate to strong westerly winds, alpine temperature -9 C, freezing level near 800 m.
Avalanche Summary
On Wednesday, a few small slabs (size 1) were triggered by skiers on southerly to easterly slopes between 1600 and 2100 m. They were 30 cm deep in steep and wind-loaded terrain. Sluffing was also noted in steep terrain.
Snowpack Summary
Highly variable snow surfaces exist, including wind-pressed snow (from primarily northeast winds), stiff wind slabs, sun crusts on steep solar aspects, and 30-50 cm of low density snow in sheltered areas at teeline and below. A crust layer can be found beneath the storm snow on sun-exposed slopes and below 1800 m.Weak layers that formed in January and December are gradually gaining strength. The layers include several surface hoar and facet layers buried 1-2 m below the surface and a crust/ facet interface near the base of the snowpack. No avalanches have been reported on these layers for the past two weeks and snowpack tests are showing improved bonding. Despite these signs, avalanche professionals are still treating these layers with respect and being cautious around shallow start zones and in big avalanche paths.
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.