Regions
South Coast Inland.
With snow and wind expected during the day on Friday watch for touchy wind slabs building in alpine, lee areas particularly in the Coquihalla area where forecasted precipitation amounts are highest.
Confidence
Moderate - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
FRIDAY: Cloudy, flurries. Accumulation 5-15 cm (highest amounts in Coquihalla area). Ridge wind moderate from the west becoming northwest. Temperature -3. Freezing level 800 m.SATURDAY: Mix of sun and cloud, light flurries. Accumulation trace. Ridge wind light from the west. Temperature -5. Freezing level 700 m.SUNDAY: Cloudy, flurries. Accumulation 5-10 cm (highest amounts in Coquihalla area). Ridge wind moderate to strong from the west. Temperature -3. Freezing level 800 m.
Avalanche Summary
There have been no new avalanche reports since the weekend when numerous loose wet avalanches up to size 2 were observed on northerly aspects along the Duffey Lake Road with rapid daytime warming that occurred on Sunday.
Snowpack Summary
The recent alpine inversion and warm temperatures across the region have created a spring-like crust on most aspects. The exception is shaded north aspects at upper elevations where the snow surface consists of dry, sugary snow (facets). Beneath the snow surface the upper snowpack is well settled and overlies the late November rain crust, now 20-50 cm deep. Recent snowpack tests in the Duffey Lake area have produced hard, resistant compression test results on small sugary, snow crystals (facets) associated with this layer. However these facets were noted to be showing signs of "rounding" or gaining strength. Treeline snow depths are approximately 1 m throughout the region.
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.