Regions
Kootenay Boundary.
It's early in the season but there is more than enough snow for avalanches. Wind slabs have recently formed in exposed terrain at higher elevations. If you are out in the mountains, please share your observations with us.
Confidence
Poor - Due to the number of field observations
Weather Forecast
The cold and dry Arctic air persists on Thursday. Freezing levels should stay below valley bottom and alpine winds should be light from NE. On Friday afternoon, a layer of warm air aloft should reach the region. Above freezing temperatures should develop around 2000m while the valleys remain cold. Valley fog may develop on Friday and should definitely be in place by Saturday. Dry and sunny conditions are expected to persist through the weekend.
Avalanche Summary
On Wednesday, ski cutting and explosives triggered several wind slab avalanches up to size 1.5. The avalanches are sliding on a firm rain crust from mid-November. Slabs were typically 5-15cm thick and were reported on a variety of aspects. These types of wind slabs may persist for a few days until temperatures warm up at higher elevations.
Snowpack Summary
10-20cm of new snowfall overlies a highly variable surface which may include surface hoar and/or facetted snow, a thick rain crust which exists to at least treeline elevation, a sun crust on steep south facing slopes, or wind-affected snow in exposed alpine terrain. At treeline elevations, the snowpack appears to typically be 1-1.5m deep. There is a thick crust from early-November in the middle of the snowpack. The limited reports we have received suggest that this crust is well bonded but you should investigate the snowpack in your local area before committing yourself to avalanche terrain. Wind slabs exist on a variety of aspects due to shifting winds may persist for a few days while temperatures remain cold.
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.