Avalanche Forecast

Issued: Nov 16th, 2017 4:00PM

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

Stephen Holeczi, Parks Canada

Banff Yoho Kootenay.

Watch for local wind loading on Friday. New snow from the last few days is either sitting on a crust or on facets and we will be watching to see how these slab problems develop over the next few days. Currently we have limited observations.

Summary

Weather Forecast

Alpine winds will pick up from the SW Friday which will transport snow onto lee aspects. Only a few cm are expected Friday at upper elevations. A larger dump of snow is scheduled for Sunday but we've all heard that before.... Temperatures should stay in the -5 to -10 range.

Snowpack Summary

10-15cm over the last 24 hours and soft storm slabs were noted in alpine features Thursday. The alpine snowpack ranges from 50-90 cm across the region. 20-40cm has exists over the Halloween crust and facets which has been seen to 2700m. The snowpack is highly variable and wind transport was noted at ridgetop.

Avalanche Summary

Forecasters kicked off a size 1.5, 30-40cm deep soft storm slab over facets today in a steeper alpine moraine feature. It was sluggish due to the slab being so soft, but higher in the alpine these slabs could have more cohesion. Lake louise and Sunshine village were noting similar type avalanches.

Confidence

Due to the number and quality of field observations

Problems

Wind Slabs

Increased winds are in the forecast which will see wind slab development of the new snow in lee aspects.

Use caution in lee areas. Recent wind loading has created wind slabs.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Storm Slabs

Much cracking and a few smaller skier triggered avalanches were noted Thurs with these soft slabs over facets and/or the halloween crust. These may gain some cohesion over the next 24 hours with the ability to propagate further distances.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Nov 17th, 2017 4:00PM