If you see 20 cm or more of new snow, consider danger to be HIGH.
Conservative route selection on simple terrain with no overhead hazard is recommended.
A layer of facets over a crust buried 60 to 90 cm deep can produce very large avalanches if triggered. Some recent storm slabs have stepped down to this layer.
Up to 70 cm of recent snowfall and strong winds built storm slabs. Additionally, up to 20 cm of new snow may fall overnight Sunday.
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 Monday.
Up to 70 cm of snow fell in the alpine last week, with rain forming a crust below 1100 m. Most of the snowfall occurred near White Pass, with significantly less in the Wheaton and Tutshi areas. The storm snow may bond slowly, as it rests on a base of weak facets and, in some isolated areas, on surface hoar.
An additional 5 to 20 cm, accompanied by strong to extreme south winds, may fall Sunday night. This would build fresh reactive storm slabs.
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 storm slabs last week stepped down to this crust, triggering large avalanches.
Total snow depths are around 100–180 cm at treeline.
Sunday Night
Cloudy with 5 to 20 cm of snow or possible rain below 1000 m. Highest amounts are for the White Pass area. 70 km/h south ridgetop wind. Treeline temperature -1 °C. Freezing level 1000 m.
Monday
Cloudy with 0 to 7 cm of snow. 60 km/h southwest ridgetop wind. Treeline temperature -1 °C. Freezing level 700 to 1000 m.
Tuesday
Cloudy with 10 to 25 cm of snow overnight and 0 to 7 cm during the day. The highest amounts will be near White Pass, with precipitation dissipating the further you go inland. 40 km/h southwest ridgetop wind. Treeline temperature -2 °C. Freezing level 700 to 1200 m.
Wednesday
Mostly cloudy. 30 km/h south ridgetop wind. Treeline temperature -6 °C.
More details can be found in the Mountain Weather Forecast.
