It is possible to trigger avalanches near ridges and roll-overs, where drifted snow sits on a crust. Stay alert to changing conditions with the arrival of new snow and wind.
Incremental snowfall over the past week with moderate winds from multiple directions has formed slabs in wind-exposed areas. Wind slabs may be reactive to human triggering, especially where the snow is not well bonded to a buried crust. In areas that received higher snow totals in the south of the region, expect this problem to be more widespread.
The next storm arrives late on Friday.
Thursday night: Mainly cloudy, light southwest wind, freezing level dropping to valley bottom.
Friday: Overcast, up to 5 cm of snow starting in the late afternoon, southwest wind increasing to moderate, treeline temperatures near -7 C, freezing level rising to 500 m.
Saturday: Cloudy, sunrise should show 10 - 20 cm of new snow which could double in depth by sunset, strong southwest wind, treeline temperatures dropping from -4 C to -10 C, freezing level dropping from 1300 m to 500 m.
Sunday: Mostly cloudy, 5-15 cm of snow, moderate southwest wind, treeline temperature near -10 C, freezing level around 500 m.
We have no new avalanche observations from this region; quite possibly due to travel restrictions. If you are out in places like the Hurley and see avalanches please drop a MIN.
The north of the region received up to 5 cm of new snow in recent convective flurries with an additional 5 cm forecast to fall by late Friday. Incremental snowfall has accumulated 10-25 cm of snow over a variety of snow surfaces that include: a thick early December crust, wind-affected surfaces in the alpine, and a potential layer of surface hoar or faceted crystals.
A couple of November crusts buried deep with the snowpack that produced large avalanches during the previous significant storm event have likely trended to dormant. Average snowpack depths in the alpine are 120-180 cm. Below treeline, 30-50 cm can be found at 500 m.
In the south of the region, recent convective flurries brought surprise accumulations of 10-30 cm of new snow, favoring areas near the Coquihalla, with an additional 5 cm forecast to fall by late Friday. A total of 20-50 cm of snow now covers previously wind-affected surfaces and the early December crust. Isolated areas that have seen higher snow totals require assessment of a more widespread reactive storm slab problem.
Having endured warmer temperatures and more rainfall, the southern part of the region is just reaching the threshold for avalanches at most elevations. Previous snow has seen extensive wind effect, exposing the early December crust clean in some areas, while piling up to 70 cm over it in others.
