Kootenay Boundary

You may be managing more than just the new snow. A reactive crust lies up to 70cm below the surface, and can produce surprisingly large avalanches.

Moderate

Light flurries are expected on Friday, although a brief pulse will bring 10-15cm of snow to region on Friday night. Expect a mix of sun and cloud on Saturday with generally clear skies on Sunday. Ridgetop winds will be strong from the west with Friday night's system and then become mainly light for the weekend. Daytime freezing levels should hover between 1300m and 1500m for the forecast period.

On Wednesday, a few skier triggered avalanches were observed in the size 1.5 to 2 range. These avalanches failed on the February crust interface mentioned in the Snowpack Discussion section. Of note, a size 2 slab avalanche northwest of Kaslo (in the South Columbia region) partially buried 2 people and completely buried another person. The avalanche, which failed on the early February interface, occurred on an east aspect at 1700m. Nobody was injured in the avalanche, but it points to the touchy conditions which also extend south into the Kootenay Boundary region. New snow and wind on Thursday and then Friday afternoon will deliver its own mix of wind slab activity, but it will also add to the likelihood and consequences of avalanches failing on the buried early February crust.

On Thursday up to 20cm of new snow fell at treeline and in the alpine. Southwest winds have likely shifted these accumulations into wind slabs in lee terrain. Rain below 1700m continued to saturate the upper snowpack. 35-80 cm below the surface you'll find a hard melt-freeze crust which formed during the 2nd week of February. This crust is quite widespread and may co-exist with weak surface hoar or facets. This variably reactive interface is the critical layer to watch in the region as it has caught a few people by surprise in recent days. A few buried surface hoar layers exist in the top 100 cm in drier areas on the west side of the region near Rossland. In other areas the notable early January surface hoar layer is 80-130 cm deep and poses a low probability/ high consequence threat. It should remain on your radar, especially in thin snowpack areas and during periods of significant warming or rapid loading.