Avalanche Forecast

Issued: Dec 2nd, 2017 3:35PM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is low. Known problems include Storm Slabs.

mgrist, Avalanche Canada

Kootenay Boundary.

The lure of powder slopes and sunny skies will be strong as the weather clears. Take a cautious approach towards more aggressive terrain - especially steep, wind-affected terrain.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

We'll see a clearing trend on Sunday afternoon and fine weather during the week.Sunday: Lingering flurries (10 cm possible over southern sections) and then clearing in the afternoon. Light northwesterly winds. Freezing levels 800m.Monday: Sunny with cloudy periods. Freezing levels around 600 m. Light northwesterly winds.Tuesday: Mainly sunny and becoming warm up high. Freezing levels rising to 1500 m. Light northerly winds.

Avalanche Summary

On Thursday we had a report of a skier-triggered Size 1 storm slab at 2000m on a north west aspect near Nelson. See here for the MIN report. The recent storm snow has been reactive to ski cutting, especially lee features which have seen wind loading.On Tuesday a naturally-triggered size 1 storm slab was observed around Kootenay Pass. The avalanche occurred on a southeast aspect at about 2100m, and is thought to have failed on the recently buried crust. A natural storm slab avalanche cycle is expected in response to recent wind and snowfall. The possibility of human triggering these storm slabs may continue into the weekend.We currently have very limited observations in this region. Please submit your observations to the Mountain Information Network (MIN).

Snowpack Summary

30 - 50cm of new snow has fallen in the past week. At higher elevations, south through west winds (gusting strong at times) redistributed the new snow, forming wind slabs on lee features.Below the recent storm snow you'll likely find a couple of widespread crusts which formed as a result of last week's rain. Late November's rain really shrunk the snowpack and has transitioned much of the snowpack from dry to moist snow. The depth of the snowpack varies greatly with elevation. Recent reports suggest the average depth is 100-170cm in the alpine, 50-100cm at treeline, and decreasing rapidly below treeline where the primary hazards are rocks, stumps, and open creeks. We currently have very limited snowpack observations within this region and it is critical to supplement this information with your own observations.

Problems

Storm Slabs

Recent wind and snowfall formed storm slabs, which may be more reactive in heavily wind-exposed terrain, or in areas where the new snow has a weak bond with underlying crusts.

Be cautious as you transition into wind affected terrain.The new snow may require several days to settle and stabilize.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Dec 3rd, 2017 2:00PM