Warm temperatures and strong solar effect may be a game changer this weekend. Stay alert to snowpack changes!
Confidence
Moderate - Wind effect is extremely variable
Weather Forecast
A modified, dry arctic air mass remains over the much of the province. Expect valley fog in the morning at lower elevations and sunshine in the alpine for most of the interior of BC. Moderate temperatures aloft, with above freezing layers of warm air, will pass through the Province during the weekend.
Avalanche Summary
Earlier in the week there were reports of skier triggered soft slabs up to size 1.5 These were mostly soft slabs 5-30 cm thick. Progressive warming in the alpine with sunny conditions may result in loose natural avalanches on steep south-facing slopes. Continued warming through the weekend may create a denser slab within the recent storm snow.
Snowpack Summary
Wind slabs, both hard and soft, may be found on any recently wind-affected terrain, especially at alpine and treeline elevations. 40-70 cm recent dry snowfall overlies a mid- and lower snowpack which is reported to be well settled. There may be some storm snow interfaces to watch in specific areas. Storm slab properties may change as the alpine gets sun and the temperatures rise. The early December weak layer (about a metre down) is now hard to find and unlikely to be triggered, except with a very heavy trigger. At the base of the snowpack, on high north aspects, basal facets may overlie glacial ice.
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 Dry
Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.