Avalanche Forecast

Issued: Dec 1st, 2021 4:00PM

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

Stephen Holeczi,

Little Yoho.

The storm will end Thursday AM, but expect avalanche hazard to stay elevated until cooler temperatures arrive and the new load settles.

Summary

Weather Forecast

Snow ending early Thursday AM, alpine winds will be around 40-60kmh decrease Thursday night into Friday. Poor to no freeze Thursday AM. Freezing levels will drop to valley bottom by the evening. Some flurries can be expected but no significant snow. Friday the temperatures will remain below freezing at valley bottom with light winds.

Snowpack Summary

Speculating 30-100cm of new snow in the high alpine based on 30mm at Bow Summit and 40mm at Sunshine in the last 24 hours. Rain occurred up to 2400m, saturating the snowpack. A midpack Nov.15 crust is found below 2100m, and the Nov. 5 crust/facet layer exists near the ground.

Avalanche Summary

Widespread natural activity and results to size 3 with explosives today. Poor visibility obscuring start zones but debris piles found in almost every path.

Confidence

Freezing levels are uncertain on Thursday

Problems

Storm Slabs

There has been an estimated 40-100cm of new snow and strong winds. this will have created sensitive slabs at treeline and above.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Very Likely

Expected Size

2 - 3

Deep Persistent Slabs

This significant load is likely overloading the Nov. 5 crust/facets just above the ground. If initiated these can cause very large, destructive avalanches. This layer will need time to adjust.

Be aware of the potential for full depth avalanches due to deeply buried weak layers.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Very Likely

Expected Size

2 - 3.5

Loose Wet

These will likely decrease in sensitivity Thursday as temperatures drop, but with no freeze overnight they will remain a problem.

Use extra caution on slopes if the snow is moist or wet.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Likely

Expected Size

1 - 2

Valid until: Dec 2nd, 2021 4:00PM