Avalanche danger will increase as the new snow piles up. Watch for signs of instability on Saturday and stick to mellow terrain while the new snow stabilizes.
Confidence
Moderate - Forecast snowfall amounts are uncertain on Saturday
Weather Forecast
Friday night: Scattered flurries bringing approximately 5cm of new snow.Saturday: Flurries delivering approximately 10 cm of new snow. Winds light to moderate from the southwest. Freezing level around 900 metres with alpine temperatures of -7Sunday: Flurries bringing another 5-10 cm of new snow. Winds moderate to strong from the southwest. Freezing level around 800 metres with alpine temperatures to -6.Monday: Cloudy with scattered flurries and another 5 cm of new snow. Winds light from the northeast. Freezing level back to valley bottom with alpine temperatures around -10.
Avalanche Summary
Reports from Thursday include a large natural cornice fall in the north of the region which succeeded in triggering a small slab, as well as evidence of wind slabs continuing to release both naturally and under skier traffic to Size 2.On Sunday and Monday, several natural wind slab avalanches up to size 2.5 were observed throughout the region. These avalanches occurred on most aspects and were mainly in the alpine but a few were at treeline. Slabs were typically 10-30 cm thick. Since then riders have been triggering wind slab avalanches up to size 1.5. One of these avalanches was remotely triggered from 40 m away.As for Saturday's outlook, fresh storm slabs are expected to be sensitive to human triggering, especially where they overlie weak surfaces and in wind exposed areas.
Snowpack Summary
New snow over Friday has now buried a range of different conditions that existed at our previous surface. In addition to wind slabs that exist on a variety of aspects in exposed terrain, the new snow will also overlie a sun crust reported on steep solar aspects as well as surface hoar recently found growing on sheltered open slopes. Surface faceting has also been reported as a result of the recent cold temperatures. A persistent weakness buried mid January is now down 20-50 cm and consists of buried surface hoar in sheltered areas, sun crust on south aspects, and/or widespread faceted old snow. It has generally stabilized but may be sensitive to triggering in isolated areas where buried surface hoar is preserved. The mid and lower snowpack are generally well settled and stable.
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.