Avalanche Forecast
Issued: Dec 10th, 2024 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs.
Parks Canada,
Avalanche Canada
Ski quality is good at the moment but be on the lookout for slab development.
A persistent weak layer made up of surface hoar or a sun crust is buried 50-70 cm deep. Remote triggering is possible in areas with a slab at or near the surface.
Summary
Confidence
Moderate
Avalanche Summary
Natural avalanche activity has tapered off with a few size 1-2.5 avalanches observed in the highway corridor in steep/extreme terrain since Sunday.
Artillery control produced excellent results on Tupper and Macdonald Sat night, with most shots producing sz 2 to sz 3 avalanches from steep start zones, running out onto valley bottom fans. Debris moved fast, likely picking up speed and mass on the buried surface hoar.
Snowpack Summary
50-70cm of new snow sits on a sun crust on steep solar aspects. In sheltered locations, this new snow sits atop large surface hoar. Strong SW winds at the end of the storm created surface slab conditions on exposed Treeline and Alpine slopes.
There is a dense, well-settled mid-pack without any significant weak layers.
The Nov 9 crust is down 1-1.5m. The base of the snowpack is comprised of several dense, melt-freeze rain crusts formed in October.
Weather Summary
A ridge of high pressure continues, with no significant change until the weekend.
Wed: Mainly cloudy with isolated flurries. Trace precipitation. Alpine high -4 °C. Ridge wind SW 10 km/h. Freezing level (FLZ)1400 m.
Thurs: Cloudy with sunny periods. No precipitation. Alpine high -4. Ridge wind SW 10. (FLZ) 1200 m.
Friday Mainly cloudy with isolated flurries. Trace precipitation. Wind SW 15-35. (FLZ) 1100 m
Terrain and Travel Advice
- Be aware of the potential for remote triggering and large avalanches due to buried surface hoar.
- Make conservative terrain choices and avoid overhead hazard.
- Watch for newly formed and reactive wind slabs as you transition into wind-affected terrain.
Problems
Persistent Slabs
65cm of snow and strong SW winds formed a slab that sits on a surface hoar layer in sheltered zones, and overlies a sun crust on steep, solar aspects. This slab may be triggered by riders where it is cohesive and stiff enough to slide on the weak layers.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Dec 11th, 2024 4:00PM
