Avalanche Forecast
Regions: Tutshi, Wheaton, White Pass East, White Pass West, Yukon.
Use conservative route selection. Choose simple, low angle terrain with no overhead hazard.
Confidence
Moderate
Avalanche Summary
Large and very large (size 2-3) natural and explosive-triggered avalanches were observed along the Klondike highway corridor on Friday.
On Wednesday and Thursday our field team observed size 1-2 storm slab avalanches and experienced whumpfing. See photo below.
On Tuesday, a remotely triggered size 2 storm slab stepped down to the persistent weak layer. Check out the MIN report.
We expect natural and human-triggered avalanches to remain possible to likely on Sunday.
Snowpack Summary
Up to 70 cm of snow has accumulated in the alpine this week, with some rain at lower elevations forming a crust below 1100 m. By Sunday afternoon, up to 15 cm of new snow is expected, with freezing levels near 1000 m, potentially bringing rain below. This accumulated snow accompanied by strong southwesterly winds have created reactive storm slabs that sit on facets, and surface hoar in isolated areas.
A persistent weak layer consisting of a crust with 20 cm of facetted snow above it is buried 60 to 90 cm and extends up to 1700 m. Some recent storm slabs have stepped down to this crust, triggering large avalanches.
The rest of the snowpack is stable, with total depths of 100–180 cm at treeline.
Weather Summary
Saturday Night
Cloudy with 0 to 10 cm of snow. 60 km/h southwest ridgetop wind. Treeline temperature -2 °C. Freezing level 1000 m.
Sunday
Cloudy with 0 to 7 cm of snow. 70 km/h south ridgetop wind. Treeline temperature -3 °C. Freezing level 500 to 1000 m.
Monday
Cloudy with 0 to 7 cm of snow. 70 km/h south ridgetop wind. Treeline temperature -3 °C. Freezing level 700 to 1000 m.
Tuesday
Cloudy with 10 to 25 cm of snow. The highest amounts will be near White Pass, with precipitation dissipating the further you go inland. 60 to 80 km/h south ridgetop wind. Treeline temperature -1 °C. Freezing level 700 to 1200 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Fresh snow rests on a problematic persistent slab, don't let good riding lure you into complacency.
- Storm slabs in motion may step down to deeper layers resulting in large avalanches.
- Remote triggering is a concern; avoid terrain where triggering overhead slopes is possible.
Avalanche Problems
Storm Slabs
70 cm of recent snowfall and wind have created reactive storm slabs with potential to step down to deeper layers.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Likely
Expected Size: 1.5 - 3
Persistent Slabs
A layer of facets over a crust buried 60 to 90 cm deep can produce very large avalanches if triggered.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 2 - 3