Avalanche Forecast

Issued: Mar 7th, 2012 9:50AM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is considerable. Known problems include Wind Slabs, Persistent Slabs and Storm Slabs.

jfloyer, Avalanche Canada

Kootenay Boundary.

The possibility for large avalanches exists with the current conditions. Use heightened caution when traveling in avalanche terrain.

Summary

Confidence

Fair - Intensity of incoming weather is uncertain on Friday

Weather Forecast

Thursday: A ridge of high pressure will bring dry and bright conditions with generally light northwesterly winds and freezing levels rising to around 2000m. Friday: A Pacific frontal system will bring around 5-10 mm precipitation, which may fall as a mix of snow and rain. Freezing levels will be up to 2000m. Winds will be strong southwesterly. Saturday: Another frontal system moves through late in the day, bringing further light to moderate amounts of precipitation, cooler temperatures and strong winds.

Avalanche Summary

No new avalanches were reported from the region on Wednesday. On Tuesday, avalanches from the west side of the region were smaller and seem to be limited to the storm snow. In the east, where more storm snow fell avalanches were much larger. For example near Wyndell a large natural slide buried a sled access road near valley bottom. Some remotely triggered and accidentally triggered slides reported by skiers that were 70 to 100 cm deep. Neighbouring areas reported a widespread, large avalanche cycle.

Snowpack Summary

Recent storm snow amounts were approximately 40 cm in the east and 10 cm in the west, with the snow line at approximately 1600 m. Valentines Surface hoar layer is now buried beneath as much as 120 to 140 cm! Stability tests show the deep layers are hard to trigger but there's huge potential for propagation.

Problems

Wind Slabs

Generally lurking below ridge crests, behind terrain breaks, and in gullies. Wind slabs are touchy and likely to stay that way with Tues wind.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

2 - 4

Persistent Slabs

Persistently weak buried surface hoar demands continued diligence and conservative decisions. The potential for remote triggering, step down avalanches, and wide propagations, makes this weakness particularly tricky to predict.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

2 - 6

Storm Slabs

Formally touchy weaknesses within the recent storm have now become less reactive, but remain a concern on convex & unsupported features.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 4

Valid until: Mar 8th, 2012 8:00AM