Avalanche Forecast
Issued: Dec 9th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs.
wlewis,
Avalanche Canada
Storm snow remains triggerable at higher elevations. Continue to be conservative
Strong winds will likely build reactive slabs around ridgelines and mid slope rollovers.
Summary
Confidence
Moderate
Avalanche Summary
Natural activity continued yesterday in areas that received snowfall like the east Purcells. Remotely triggered avalanches continue to occur at high elevations, above the rain crust in nearby regions.
Small, naturally triggered deep persistent slabs were observed on basal facets yesterday, near Invermere. This is likely only a problem in very shallow snowpacks like the east Purcells.
Snowpack Summary
Strong winds will redistribute 20-40 cm of recent snow into deeper deposits on north and east facing slopes. This snow covers a widespread crust from the rain. In the south this crust is up to 25 cm thick and extends to ridgetop. The crust thins to around 5 cm as you move north from Revelstoke, and is observed up to 2300 m. Near Invermere the crust has been observed to around 2100 m.
The greatest concern is a large and weak layer of surface hoar, found 45-80 cm deep. This surface hoar sits on a thin sun crust on steep south-facing slopes.
The mid-pack is generally well-settled. Lower in the snowpack a crust with weak facets beneath it can be found 20 cm off the ground.
Weather Summary
Saturday Night
Mostly cloudy with up to 10 cm of snow possible overnight. Treeline temperatures around -9 °C. Southwest winds 40-60 km/h.
Sunday
Cloudy with another 5 cm of snow possible. Winds ease to 40 km/h from the west. Treeline temperatures around -4 °C.
Monday
Mostly cloudy with no snow expected. Light and variable winds. Treeline temperatures reach -6 °C.
Tuesday
Clearing skies with no snow expected. Light and variable winds. Treeline temperatures reach -7 °C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Continue to make conservative terrain choices while the storm snow settles and stabilizes.
- Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
- Use careful route-finding and stick to moderate slope angles with low consequences.
Problems
Storm Slabs
Storm snow sits overlies large, weak surface hoar. Triggering is most likely at elevations where the rain crust disappears (above 1900-2100m)
Watch for reactivity in the wind affected storm snow on north and east facing slopes
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 10th, 2023 4:00PM
