Regions
South Coast Inland.
Temperature inversion conditions have moistened the snow surface at higher elevations. This is likely on all aspects in the north of the region and predominantly on southerly slopes in the south of the region.
Confidence
High - The weather pattern is stable
Weather Forecast
MONDAY: Clear skies, light southwesterly winds increasing to moderate in the afternoon, freezing level around 3700 m with inversion conditions.TUESDAY: Partly cloudy, light southwesterly winds, freezing level around 2300 m with inversion conditions.WEDNESDAY: Mostly clear skies, light northwesterly winds, freezing level rising to 3500 m over the day with inversion conditions.
Avalanche Summary
Numerous loose wet avalanches up to size 2 were observed on northerly aspects along Duffey Lake Road on Sunday. No new avalanches were observed on Friday or Saturday. Numerous small loose wet avalanches (size 1) were observed on steep south and west-facing slopes on Wednesday and Thursday. Glide avalanches were observed on steep, smooth rock slabs to size 2 around the Coquihalla on Thursday.
Snowpack Summary
Warm air temperatures and sunny skies have created surface crusts on southerly slopes, which may melt with warm air temperatures and under sunny skies. North slopes were also affected in areas where cloudy skies prevailed on Sunday, due to the greenhouse effect. It appears that this mostly occurred in the northern half of the region. For the southern half of the region, northerly slopes likely remained cold. Moderate wind speeds from the south may have produced localized wind slabs on northerly lee features. In shady slopes, surface hoar to 20 mm and near-surface faceting have been observed around treeline and in the alpine. Cornices may be weakening with the warm air temperatures. The recent snow has formed a strong bond to the late November rain crust, which is now 30-50 cm deep. 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.
Loose Wet
Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.