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Archived

Avalanche Forecast

Nov 28th, 2011–Nov 29th, 2011
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low

Regions: Kootenay Boundary.

Confidence

Poor - Due to limited field observations

Weather Forecast

Light to moderate precipitation is forecast for tuesday afternoon with moderate southwest winds and freezing levels reaching 1200m.On wednesday and thursday a ridge is expected to dominate the area bringing clear skies, light to moderate northwest winds and freezing levels at or near surface.

Avalanche Summary

Numerous size 3 natural avalanches were reported north of the region on friday on a suspected early season crust that has been reactive in a few regions throughout the province. At this point we have extremely limited observations from the Kootenay-Boundary region; but the recent weather has been sufficient to produce significant avalanche activity at treeline and in the alpine. If you have any avalanche observations to report, please email us at: [email protected].

Snowpack Summary

Generally there is about 150 cms in the alpine, and treeline has been showing some variability between 50 -150 cms. There are locations in the alpine that have 200 cms plus already. On friday we received new information from the Selkirks south of Revelstoke that there was indeed a major avalanche cycle up to size 3.5 during the last storm, but it appears that most of the avalanches were sliding on a layer that is near the ground; perhaps a rain crust from October. This crust has also been highly reactive in the Lizard Range to the east. At this point we have heard no reports of this lower layer existing in the Kootenay-Boundary region; however, I think that we should at least be curious about the possibility of its existence as we gather information from data-sparse areas.Sunday's big system produced but a few centimetres of snow with freezing levels rising to 1800m, but winds were strong from the southwest. In the mid and upper snowpack, expect wind slabs and storm slabs resulting from this wind event and last weeks storms. With tuesday's forecast snow and wind, expect further wind and storm slab development.We hope to get some more information soon, as operators start getting out into the field. Any info from the field is welcome in our office. Let me know what you're seeing out there! [email protected]

Avalanche Problems

Wind Slabs

Strong winds and warming temperatures will create new wind slabs on lee slopes and cross-loaded terrain features.

Aspects: North, North East, East, South East.

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 3

Storm Slabs

Slabs have been developing over the past few storms. These slabs are probably averaging 50-80 cms. We have very little information regarding avalanche activity in this region.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible

Expected Size: 1 - 3