Avalanche Forecast
Regions: Badshot-Battle, Bonnington, Crawford, Goat, Grohman, Kokanee, Kootenay Boundary, Kootenay Pass, Moyie, Norns, Retallack, Rossland, St. Mary, Valhalla, Whatshan, Ymir.
The variable distribution of buried weak layers makes assessing avalanche danger tricky. Use caution on steep open slopes at treeline and below, where these layers have been most active.
Confidence
Moderate
Avalanche Summary
Following a widespread avalanche cycle last Wednesday, several human-triggered avalanches have been reported on a buried surface hoar layer.
These avalanches, occurring on north-facing terrain, have been approximately 50 cm deep and range from size 1 to 2. Notably, two avalanches were remote-triggered, including one from 100 meters away by a group of skiers.
Remote-triggered avalanches are a strong sign of an unstable snowpack.
Snowpack Summary
Up to 10 cm of fresh snow has fallen on top of storm snow from earlier in the week. The upper snowpack continues to settle and bond with recent mild temperatures. Wind-affected snow is present at the surface in exposed terrain at higher elevations. At lower elevations, surface conditions range from crusty to moist, depending on the time of day and local temperatures.
Down 50 to 100 cm there are weak layers of facets, crusts, and in some places surface hoar. The distribution of these layers is highly variable throughout the region. Areas currently showing the greatest reactivity are the Goat Range, Bonningtons, and Rossland Range.
Treeline snow depths range from 100 to 180 cm.
Weather Summary
Sunday Night
Cloudy with 0 to 5 cm of snow. 20 to 30 km/h southwest ridgetop wind. Treeline temperature -5 °C.
Monday
Cloudy with 0 to 2 cm of snow. 20 to 30 km/h southwest ridgetop wind. Treeline temperature -5 °C.
Tuesday
Cloudy with up to 10 cm of snow. 20 to 40 km/h southwest ridgetop wind. Treeline temperature -3 °C.
Wednesday
Mix of sun and cloud. 20 to 40 km/h southwest ridgetop wind. Treeline temperature -5 °C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Approach steep and open slopes at and below treeline cautiously, as buried surface hoar may exist.
- Surface hoar distribution is highly variable. Avoid generalizing your observations.
- Be aware of the potential for large avalanches due to a buried crust.
- Be careful as you transition into wind-affected terrain.
Avalanche Problems
Persistent Slabs
Surface hoar, and in some areas facets over a crust, have produced large avalanches and shown reactivity in tests in the past few days. Be especially cautious in steep openings at treeline and below.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible
Expected Size: 1.5 - 3
Wind Slabs
New snow and wind are expected to form fresh, reactive wind slabs at upper elevations.
Aspects: North, North East, East, South East, South, North West.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 1 - 1.5