Conditions may vary significantly from one slope to another. Avoid areas where the recent snow has been drifted by wind and investigate deeper weak layers before committing to terrain.
Moderate winds from the south have drifted snow into slabs on lee features that may be possible to trigger at upper elevations. Avoid areas that are prone to human-triggering, such as steep, rocky, or convex features near ridge crests and roll-overs.
Very large avalanches over the past week suggest that a buried crust formed in early November and weak snow at the ground are reactive persistent and deep persistent weak layers. We have limited information about the distribution of this snowpack structure in the region. Keep in mind that small avalanches have the potential to step-down to these deeper layers, producing large, destructive avalanches.
Saturday night: Mostly cloudy, isolated flurries with up to 5 cm of snow above 1500 m, moderate southwest winds, freezing level dropping to 1400 m.
Sunday: Mostly cloudy, isolated flurries with up to 5 cm of snow above 1400 m, moderate southwest winds increasing to strong in the afternoon, freezing level dropping to 1200 m.
Monday: Mostly cloudy, 5-10 cm of snow above 1100 m, light south winds, freezing level dropping to 800 m.
Tuesday: Partly cloudy, 5-10 cm of snow, light southwest winds, freezing level around 800 m.
Observers in the southern half of the region have reported no recent avalanche activity. Outside of the region near Thutade Lake, operators triggered two large (size 2) avalanches with explosives on Friday that released on weak snow at the ground.
On Wednesday, a series of notable avalanches were reported near Ningunsaw. These were explosive-triggered and natural releases that resulted in very large deep persistent slab avalanches (size 3-3.5), also failing on weak snow near the ground.
Our eyes and ears in the mountains are limited this winter due to fewer professional observations. If you go out in the mountains, please share your observations on the Mountain Information Network (MIN). Photos are especially helpful!
Favored areas in the west and north of the region have seen 10-20 cm of snow (5 cm closer to Smithers), accompanied by light to moderate southeast winds. Trace amounts are expected to accumulate overnight and into Sunday as the freezing level drops back down to 1200 m. The new snow rests on a recent crust or hard, wind-packed snow that was buried earlier this week (Dec. 4). Where winds have drifted the recent snow into slabs on lee features, wind slab avalanches may be possible to trigger.
Extensive wind-scouring and several days of above freezing temperatures have promoted rapid settling in the snowpack. The bottom half of the snowpack reportedly consists of weak snow interrupted by a crust from early November. Further north and east in the region, weak snow developing near the ground has produced very large deep persistent slab avalanches. The extent of this snowpack structure in the region is not well-known. Smaller avalanches in the new snow may have the potential to step-down to deeper layers and to produce large, destructive avalanches. Large alpine slopes where the snow transitions from thick to thin are most suspect.
Snowpack depths vary substantially with aspect, elevation, and wind exposure, ranging from 60 cm in eastern parts of the region to over 100 cm in western parts of the region. Lower elevation terrain may still be below the threshold for avalanches.
