New snow and wind will be forming fresh and reactive storm slabs. Choose simple terrain and avoid overhead hazard.
A complex snowpack has produced large avalanches and several incidents in the last week, including a fatal avalanche near Pemberton on Monday.
A significant load is being applied to a persistent weak layer that is now buried between 60-150 cm. It is likely that avalanches will run on this layer during this weekend's storm.
Significant amounts of new snow with strong winds will form widespread storm slabs that will most likely be very reactive.
Saturday night: Snow, 10-20 cm in most areas, lighter snowfall in areas north of Pemberton, moderate to strong southwest wind, freezing level 700 m.
Sunday: Flurries, 5-10 cm, moderate to strong southwest wind, alpine high temperature near -7, freezing level 1200 m.
Monday: Flurries, up to 5 cm, light southwest wind, alpine high temperature near -3, freezing level 1000 m.
Tuesday: Flurries, up to 5 cm, moderate southwest wind, alpine high temperature near -6, freezing level 1000 m.
Avalanches are expected to be widespread on Sunday.
Numerous storm slab avalanches, natural and explosive triggered size 2-4 (!) were reported on Friday and Saturday.
There was a fatal avalanche north of Pemberton in the Railroad Pass area on Monday that resulted in two fatalities. It was reported to be a size 2 persistent slab avalanche on a west aspect, around 1650 m. The RCMP press release can be viewed here and the Avalanche Canada report can be found here.
A size 2 avalanche was triggered on Monday by a skier on a northwest aspect in the alpine on Mt. Matier (Duffey). The avalanche occurred on a northwest aspect and was likely a wind slab avalanche. It carried the skier over cliffs resulting in several injuries. A MIN report detailing this incident can be found here.
A few persistent slab avalanches were reported last week, mostly in the north of the region near the Hurley, but also near Allison Pass. They were triggered by riders, heavy machinery, and naturally. The slabs were generally 60 to 90 cm deep, around 2000 m, and released on the weak layers described in the snowpack summary.
15-30 cm of new snow overnight Saturday and over the day Sunday will bring recent storm snow totals to around 60-100 cm. This snow may be sitting on surface hoar below treeline. Large snowfall amounts combined with strong southwest winds will most likely form widespread and reactive storm slabs.
A melt-freeze crust from early December is found around 80 to 180 cm deep in the snowpack. This crust may have surface hoar or sugary faceted grains sitting above it. This persistent weak layer is most prevalent in the north (e.g., Duffey Lake, Hurley) and found to a lesser extent in the south of the region.
The remainder of the snowpack is generally well settled.
