Avalanche Forecast
Issued: Dec 15th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Persistent Slabs.
bchristie,
Avalanche Canada
Start with small slopes, and gather information. Continue to be wary of a buried layer of surface hoar.
In times of uncertainty conservative terrain choices are our best defense.
Summary
Confidence
Avalanche Summary
The surface hoar continues to cause concerning results in snowpack tests. Despite a lack of avalanche observations, we presume that large, human triggered avalanches are still possible in areas where dense, slabby snow sits over this layer of weak, feathery crystals.
Snowpack Summary
Recent snow accompanied by strong wind has formed wind slabs. This covers previous old wind slabs, sun crusts on steeper south aspects, and surface hoar in sheltered areas. Down 25-50 cm a rain crust has been observed and exists up to 2100 m throughout this region. The thickness of this crust tapers with elevation gain.
A concerning layer of surface hoar is now buried 60 to 90 cm deep at upper elevations and may be more reactive to human triggering above 2100 m.
The lower snowpack is a mix of rounded and faceted grains. A hard crust may be found near the ground.
Treeline snowpack depths are variable and generally range between 70 and 120 cm. Snowpack tapers rapidly as you move lower in elevation.
Weather Summary
Friday Night
Partly cloudy. No new snow expected. Light to moderate southwest ridgetop wind. Treeline temperature around -5°C. Freezing level between 1000 and 1500 m.
Saturday
Possible clear periods in the morning, cloudy through the day. No new snow expected. Ridgetop wind tapering off to very light southwest. Treeline temperature around -3°C. Freezing level rising to around 1300 m.
Sunday
Mostly cloudy. Possible trace of snow expected. Light variable ridgetop wind. and temperatures near +2 C. Treeline temperature around -3°C with alpine temperature inversion.
Monday
Mostly cloudy. Possible trace of snow expected. Light to moderate south or southeast ridgetop wind. Treeline temperature around -1°C with alpine temperature inversion.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Stay off recently wind loaded slopes until they have had a chance to stabilize.
- Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
- Use conservative route selection and resist venturing out into complex terrain.
Problems
Wind Slabs
Moderate southwest winds overnight continued to build reactive wind slabs. They may be thicker and more reactive in north and east-facing terrain features.
Aspects: North, North East, East, West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
A persistent weak layer of surface hoar is buried down 60-90 cm in the snowpack. It may be most triggerable where the recent rain crust thins, or disappears at 2100 m and higher.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 16th, 2023 4:00PM
