Kootenay Boundary

Large storm slabs were reactive over the weekend and there's some uncertainty about how long they will persist. Cautious decision making and conservative terrain selection is recommended.

Moderate - Timing, track, or intensity of incoming weather system is uncertain

An unsettled pattern opens the door to a string of relatively small low-pressure systems that should deliver modest snowfall to the region through the forecast period. MONDAY: Scattered flurries with 2-8 cm of new snow, moderate southwest winds, alpine temperatures around -10 C.TUESDAY: Scattered flurries with 2-6 cm of new snow, moderate southwest winds, alpine temperatures around -10 C.WEDNESDAY: 5-15 cm of new snow, moderate southwest winds, alpine temperatures around -10 C.

A widespread natural avalanche cycle occurred on Friday night into Saturday morning, with size 2-3 storm slab avalanches on a variety of aspects and elevations. Some crowns were over a metre thick, but observers suspect the slabs failed within the storm snow and did not step down to any deeper layers. Storm slabs were also reactive to human triggers, producing size 1-1.5 slab avalanches on convex and wind-loaded features at treeline (30-60 cm deep). Natural activity has likely tapered off, but storm slabs will likely remain primed for human triggering.

A wide-ranging 35 to 100 cm of snow has fallen in the past week. The new snow is rapidly settling into a denser slab which sits over a variety of old interfaces including sun crusts, surface hoar, and weak faceted snow. Winds shifted from the northwest to the southwest during the storm, forming thicker deposits in lee areas at higher elevations. The new snow also has the potential to wake up the mid-February crust layer buried about a metre deep on solar aspects and at lower elevations. Areas with a shallow snowpack (less than around 170 cm) generally have a deep persistent weakness of facets near the ground. There are a number of great MIN reports from Thursday and Friday here.