Avalanche Forecast

Issued: Nov 11th, 2021 4:00PM

The alpine rating is below threshold, the treeline rating is below threshold, and the below treeline rating is below threshold. Known problems include Wind Slabs and Loose Dry.

Lisa Paulson,

Banff Yoho Kootenay.

Strong wind and flurries expected Friday. Climbers consider the potential for spindrift and pockets of wind slab between pitches in route selection. Still rugged for riding, hopefully it will change after the storm this weekend!

Summary

Weather Forecast

A weak frontal system will pass Friday bringing up to 10 cm with strong SW wind and relatively warm temperatures (-5C range) with a slight inversion for the day.Â The main event to watch is the storm predicted to arrive Sunday lasting through to Tuesday where 60-80 cm may fall. Stay tuned... the weather models vary with timing and intensity.

Snowpack Summary

Up to 30cm of snow over the last 5 days in the alpine, sitting over a melt freeze crust that may be present to ~2500 m. Below the crust is 10-30cm of facetted snow. We expect 60-70cm of snow in the alpine. Windslabs 20-50 cm thick, isolated to immediate lees, reported at higher elevations. Below threshold for avalanches at treeline and below.,

Avalanche Summary

We have very limited observations - thank you for the MIN reports! Lake Louise ski patrol has triggered windslabs avalanches up to size 1.5, on average 40 cm deep running on the ground. At Bow Summit on Wednesday there was a third hand report of someone going for a ride in a small windlslab.

Confidence

Problems

Wind Slabs

Although small, these avalanches could give someone a rough ride through the rocks. The most attractive slopes to ride are where this problem likely exists. Overhead cornice failure triggered by increased wind may trigger windslab pockets below.

Use caution in lee areas in the alpine. Recent storm snow has formed wind slabs.

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

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

1 - 2

Loose Dry

Strong alpine winds coupled with some snow may trigger loose dry avalanches in steep confined terrain features Friday. Climbers should consider these factors in their route selection.

Be careful of loose dry sluffing in steep, confined or exposed terrain.