Kootenay Boundary

Watch for fresh, touchy wind slabs forming in lee terrain on Sunday.

Moderate - Forecast snowfall amounts are uncertain

Saturday night: Cloudy with scattered flurries bringing approximately 5 cm of new snow. Winds light to moderate from the southwest. Sunday: Flurries bringing approximately 5 cm of new snow over the day. Winds light from the southeast. Freezing level to 900 metres with alpine temperatures of -6. Monday: Continuing scattered flurries bringing up to 5 cm of new snow. Winds light to moderate from the southwest. Freezing level to 600 metres with alpine temperatures of -8. Tuesday: Cloudy with sunny periods. Winds light to moderate from the northwest. Freezing level to 400 metres with alpine temperatures of -10.

Reports from Friday show diminished storm slab avalanche activity, with two ski cut Size 1 slabs reported in the Bonnington Range and in the Kootenay Pass area. The Bonnington slide took place on a steeper northwest facing slope at 2150 metres. The MIN report of the Kootenay Pass slide suggests it took a group effort to produce the release. Reports from Thursday included observations of both explosives and skier triggered storm slabs generally Size 1.5-2. A ski cut Size 2 wind slab also drew attention to the effect of recent northerly winds in the region.For Sunday, expect conditions to become touchier as the day progresses and new snow accumulates. Although our persistent slab problem is no longer listed, deeper instabilities in the snowpack remain a lingering concern, particularly in areas with an unusually shallow snowpack and where faceted (sugary) snow remains preserved near the base of the snowpack.

Solar radiation has created a sun crust on steep solar aspects while surface hoar has been observed at up to 15 mm on shaded aspects. Below these surfaces, 30-50 cm of recent snow overlies a (February 18) sun crust on solar aspects, with around 70 cm overlying a widespread (February 10) melt-freeze crust on shaded aspects. Recent variable winds have promoted wind slab formation in this storm snow on a range of aspects in wind-exposed terrain and in some areas scoured the new snow down to the crust. Below the wind effect, reports suggest the storm snow is generally well bonded to the underlying crust layers.The early-February surface hoar layer is now down approximately 80-100 cm. This layer was reactive during the warm storm last week but now appears to have gone dormant. Areas with a shallow snowpack (less than around 150 cm) generally have a weak snowpack structure with a layer of sugary facets near the ground.