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Archived

Avalanche Forecast

Feb 22nd, 2016–Feb 23rd, 2016
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate
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
2: Moderate
The avalanche danger rating below treeline will be moderate
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

Regions: Kootenay Boundary.

Conservative route finding is essential to safe travel. Daytime warming and solar input may make buried weaknesses more reactive

Confidence

Moderate - Due to the number and quality of field observations

Weather Forecast

A bit of cloudy weather today and tomorrow, with no precipitation forecast. A ridge of high pressure will rebuild over the province bringing  mostly sunny skies with daytime warming and night time cooling for the remainder of the week. Freezing levels may rise to 1200 metres during the day,  but should drop to valley bottoms overnight.

Avalanche Summary

Numerous skier controlled, skier accidental, explosive controlled and naturally triggered storm slab avalanches have been reported in the past few days in sizes up to size 3. Yesterday there were 3 skier accidentals in the Bonnington range . A snowmobile triggered 1.5 - 2 was reported in the area east of Kokanee park, on a wind loaded knoll. Most likely these failed as a result of heavy storm and wind loading throughout the past week.. A number of these avalanches released on the February crust interface mentioned in the Snowpack Discussion section. The combination of wind, rapid loading, warm temperatures and increased radiation on solar aspects makes for a perfect recipe for large avalanches.

Snowpack Summary

A considerable amount of snow fell during the past week, with the eastern part of the region receiving the most out of the storms.  Reports from across the region indicate that moderate to strong south west winds have redistributed the surface snow into touchy wind slabs. The last storm arrived with considerably less wind and may now be hiding previously formed pockets of wind slab. A melt-freeze crust that formed during the 2nd week of February has been reported at various levels from 50 to 120cm. This crust is widespread and may co-exist with surface hoar or weak facets, especially at treeline and below. This reactive interface is a critical layer to watch in the region, and has been the active layer for some very large avalanches recently. Buried surface hoar layers exist in the drier areas on the west side of the region near Rossland and are worth keeping in mind.  Surface hoar growing up to 6mm has been reported in the past 2 days throughout the region. Sun crust may exist on solar aspects at the surface and has also been reported in the region 20cm below the surface.

Avalanche Problems

Wind Slabs

Wind slabs are still in the news with recent avalanche activity at tree line and above.  Approach all lee terrain with suspicion until things settle down.
Avoid freshly wind loaded features.>Stay off recent wind loaded areas until the slope has had a chance to stabilize.>Sluffs may trigger deeper instabilities.>

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

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 3

Persistent Slabs

Up to 50cm of recent storm snow in parts of the region is beginning to settle and bond.  Give it time to stabilize.
Be aware of the potential for full depth avalanches due to deeply buried weak layers.>Use conservative route selection, stick to moderate angled terrain with low consequence.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 2 - 5

Cornices

Cornices have grown large in the past week and may become fragile with daytime heating.  Keep them at a wide and respectful distance.
Do not travel on slopes that are exposed to cornices overhead.>Extra caution needed around cornices with current conditions.>

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

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 4