Archived

Avalanche Forecast

Nov 27th, 2014–Nov 28th, 2014

Alpine

4: High

The avalanche danger rating in the alpine will be high

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

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: Banff Yoho Kootenay.

Touchy windslabs continuing to build. Another 25 cm with gusty SW winds expected before storm ends mid-day Friday. For climbing, it's a good time to stay clear of avalanche terrain and skiers should avoid open windloaded slopes and overhead hazard.

Weather Forecast

Another 25 cm is forecasted for the region tonight and ending mid-day Friday. Winds will be SW light - moderate SW with gusts to 60 km/hr. On the heels of the snow ending, the temperatures will plummet to -30 for Saturday & Sunday with highs of -20C. Monday temperatures start to warm slightly.

Snowpack Summary

There is approximately 30 cm of storm snow (more at higher elevations closer to the divide). The new snow is not bonding well to the underlying weak faceted midpack that blankets the region. At the base is the early November rain crust, which also poses a step down concern.

Avalanche Summary

Avalanches to size 2 were observed today in lee terrain in the alpine. Avalanches were failing at the storm snow interface and some stepped down to the Nov 6 rain crust (40-50 deep).

Confidence

Intensity of incoming weather systems is uncertain

Avalanche Problems

Wind Slabs

Windslabs continue to develop with ongoing storm. Slabs are now up to 40 cm thick. Expect the potential for propagation to increase as they become more dense. Watch for slabs in all leeward areas in addition to loose snow avalanches in gullies.

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

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 3

Deep Persistent Slabs

Any wind/storm slab triggered will likely step down to the Nov 6 rain crust or to the ground and entrain the weak faceted snow pack. This would be a nasty ride through boulders and trees.... Avoid all open avalanche terrain during the storm.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 3