Avalanche Forecast

Issued: Dec 9th, 2015 4:39PM

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

Lisa Paulson, Parks Canada

Banff Yoho Kootenay.

With some careful route finding to avoid the problems described, you can find some great skiing! Expect less sluffing from cliffs tomorrow as the wind backs off.

Summary

Weather Forecast

Significant snow fall has subsided, temperatures will continue to cool and winds will taper. Cloudy skies and light flurries are forecast for the remainder of the week.

Snowpack Summary

The Dec 3rd interface is buried by 35 - 70 cm of snow (the greatest amount around Bow Summit). Lots of settlement of the new snow increasing it's slab like property. The Dec 3 layer is the key weakness and it consists of facets and large surface hoar below 2000m, wind effect in the alpine, and suncrusts on steep S & SW aspects.

Avalanche Summary

Size 1 wind slabs in immediate lees of alpine terrain ski cut and with explosive work in the Louise area. Size 1 sluffs off steep cliffs triggered by wind gusts today. Some cracking has been observed in a steep below treeline glades where the Dec. 3rd surface hoar is present. Again, limited observations in the alpine due to poor visibility.

Confidence

Due to the number of field observations

Problems

Wind Slabs

30-70 cms of storm snow in the alpine and at treeline was blown by moderate to strong S-SW-SE winds in immediate lees of prominent features and ridgelines.

Use caution in lee areas. Recent wind loading has created wind slabs.Be cautious as you transition into wind affected terrain.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Storm Slabs

30- 70 cm's of new snow is settling into a cohesive slab. It will be most reactive where there is more than 30 cm of new snow and below 2000m where it overlies the Dec. 3rd surface hoar or facets, found in sheltered terrain or northerly aspects,.

Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Valid until: Dec 10th, 2015 4:00PM