Avalanche Forecast
Regions: Tutshi, Wheaton, White Pass East, White Pass West, Yukon.
Stick to simple terrain and avoid overhead slopes. It's possible to remote-trigger very large avalanches from long distances away.
Check out this MIN report showcasing a recent avalanche.
Confidence
Moderate
Avalanche Summary
On Wednesday, the Yukon Team via snowmobile remotely triggered a large (size 3) persistent slab avalanche from 100 m away near Bryant Lake. It was triggered from flat terrain at the col on an ENE aspect at 1500 m. The crown depth was 1 to 2 m, the width was 400 m and it ran 400 m down slope. It slid on the December facet/ crust interface.
A natural avalanche cycle up to size 3 occurred during the storm earlier in the week.
Human-triggered avalanches remain likely on Friday.
Snowpack Summary
Up to 40 cm of storm snow has been redistributed by strong southwest winds building thick wind slabs on leeward slopes.
A persistent weak layer consisting of a crust with faceted snow above it is buried 60 to 100 cm, and extends up to 1750 m. Recent snowpack tests have shown moderate results with sudden collapse behaviour. A large (size 3) remotely triggered avalanche is an indicator that this persistent slab is reactive.
Total snow depths are around 160–190 cm at treeline.
Weather Summary
Thursday Night
Clear. 15 to 40 km/h northwest ridgetop wind. Treeline temperature -18 °C.
Friday
Mix of sun and cloud. 15 to 20 km/h southwest ridgetop wind. Treeline temperature -10 °C.
Saturday
A mix of sun and cloud. 20 km/h southwest ridgetop wind. Treeline temperature -9 °C.
Sunday
A mix of sun and cloud. 10 to 25 km/h southwest ridgetop wind. Treeline temperature -8 °C. Strong alpine above freezing layer.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Remote triggering is a concern; avoid terrain where triggering overhead slopes is possible.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
- Fresh snow rests on a problematic persistent slab, don't let good riding lure you into complacency.
- In times of uncertainty, conservative terrain choices are our best defense.
Avalanche Problems
Persistent Slabs
A layer of facets over a crust buried 60 to 100 cm deep and if triggered will produce large and destructive avalanches.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible - Likely
Expected Size: 2 - 3.5
Wind Slabs
Reactive wind slabs may exist. North through east slopes are very loaded with deep deposits of snow but changing winds could also load south facing slopes on Friday.
Aspects: North, North East, East, South East, South.
Elevations: Alpine, Treeline.
Likelihood: Possible - Likely
Expected Size: 1.5 - 2.5