As snowfall tapers after the weekend, sustained wind will likely continue to form reactive slabs. Stick to conservative terrain as the snowpack adjusts to the recently added snow load.
A couple of problematic layers may be found around 80 to 180 cm deep, including weak layers of surface hoar and faceted grains above a hard melt-freeze crust. With the addition of a significant load of new snow, large avalanches may run naturally on these layers.
Significant amounts of recent snow with ongoing strong winds are forming widespread storm slabs that will most likely remain reactive.
Flurries may bring another 5-10 cm of new snow, bringing storm totals to over 70 cm. Large recent snowfall amounts combined with ongoing strong southwest winds have been forming reactive storm slabs and growing cornices at ridgetop. In sheltered areas below treeline, recent snow may be sitting on surface hoar.
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.
Sunday night: Flurries, up to 5 cm, moderate to strong southwest wind, freezing level 600 m.
Monday: Flurries, up to 10 cm, moderate southwest wind, alpine high temperature near -4, freezing level 1000 m in the north, 1500 m in the south.
Tuesday: Scattered flurries, moderate southwest wind, alpine high temperature near -5, freezing level 1300 m.
Wednesday: Snow, 5-10 cm, moderate southwest wind, alpine high temperature near -3, freezing level 1500 m.
Over the weekend, a large natural storm slab avalanche cycle was observed up to size 3 in much of the region and up to size 4 near Pemberton.
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.
