Avalanche Forecast

Issued: Dec 7th, 2018 4:00PM

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

stephen holeczi, Parks Canada

Banff Yoho Kootenay.

The annual rotting of the snowpack is in full effect. As this happens watch for areas that still have a slab sitting over facets.

Summary

Weather Forecast

Another cold night in the forecast with AM temperatures (-15 to -20C) but inverted in the alpine (-5 to -10C).Â SW winds will increase into the moderate range Saturday afternoon into Sunday.Â A warming trend will continue through to Monday with no real snow in the forecast....

Snowpack Summary

No new snow in several days. Thin wind slabs in immediate lee areas at treeline and above. The October 26th crust/facet layer is ~30 cm above ground. In many areas the entire snowpack is faceting and becoming quite weak. Snow depths range from 50-85 cm at 2000 m.

Avalanche Summary

A skier accidental was reported Wednesday on the slopes skiers left of Bow Summit. It was a size 1.5 and likely failed on the Oct 26th crust/facets. Additionally some small thin wind slabs were reported in the Observation Peak and Sunshine Village areas. A few small loose dry avalanche have also been observed.

Confidence

Problems

Wind Slabs

Some light wind transport on Tuesday created small thin wind slabs in lee areas at higher elevations. They appear to be stubborn to ski cutting and are generally thin and small.

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 1.5

Deep Persistent Slabs

It is still possible to trigger this layer but it will be in isolated, steep spots and often adjacent to thin rocky areas. Be cautious in steep terrain where a stiffer, more cohesive slab exists over the weak faceted snow at the base of the snowpack.

Whumpfing is direct evidence of a buried instability.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1.5 - 2

Valid until: Dec 8th, 2018 4:00PM