Avalanche Forecast

Issued: Nov 23rd, 2017 4:12PM

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

snow safety, Parks Canada

Banff Yoho Kootenay.

Widespread avalanche cycle today running on the Halloween crust to size 3. Numerous wet avalanches observed below treeline. Up to 75 cm recently in the alpine & 16-24 mm below treeline. The snowpack needs time to adjust - make conservative choices.

Summary

Weather Forecast

As of 7 am Thursday, temperatures have started to cool, and as of 4 pm it's snowing in Lake Louise village. Expect cooler temperatures and some flurries over the next few days along the divide. Winds will remain moderate to strong from the SW.

Snowpack Summary

There is up to 75 cm new in the alpine from the recent storm and rain soaked snow below 2200 m throughout the region. The main feature of concern has been a facet layer associated with the halloween rain crust in the bottom third of the snowpack. Numerous slab avalanches have occurred on this layer and wet loose avalanches below 2200 m.

Avalanche Summary

Throughout the region there were numerous natural and controlled avalanches to size 3 today running far down the track and well into the run-outs as they incorporated the wet snow below treeline. It will take some time for the snowpack to cool and adjust to the new load.

Confidence

Due to the quality of field observations

Problems

Persistent Slabs

This is an active avalanche problem that has become over loaded. It is the main reason people should avoid all avalanche terrain. Watch overhead hazard, avalanches will run further than expected incorporating slushy wet snow.

Avoid all avalanche terrain.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Wind Slabs

Lots of new snow in the alpine to move around. Winds will remain moderate to strong (SW) over the next few days. Reactive windslabs should be expected near all ridges and gully areas.

Avoid freshly wind loaded features.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Loose Wet

The snow below treeline is saturated and will need time to freeze. Ice climbers in particular should avoid gully climbs for the next 48-hours.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Nov 24th, 2017 4:00PM