Avalanche Forecast

Issued: Feb 8th, 2017 4:00PM

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

brian webster, Parks Canada

Banff Yoho Kootenay.

With rising temperatures and forecasted snow expect the danger level to increase. Conservative route choices are in order.

Summary

Weather Forecast

A low pressure system will track across the south part of BC bringing rising freezing levels, significant snow-fall , and strong south and sw winds. Freezing levels rising to 1500 m in Lake Louise on Thursday. 20-30 cm of snow are forecasted to fall by Friday. The avalanche danger will increase through the end of the week.

Snowpack Summary

10-30 cm of recent storm snow overrides a mid pack that is largely weak and facetted. Moderate southerly winds will have created some soft slabs in alpine lee features.

Avalanche Summary

Explosive control on Tuesday produced small results up to size 2 across the forecast region. On Wednesday morning a natural Class 3.5-4 avalanche was triggered on the Mt Stephen Road Avalanche Path. This was triggered at 2600m by a large serac fall and ran down to the bottom of the run-out. Debris on highway was 50m wide X 1.5m deep.

Confidence

Problems

Deep Persistent Slabs

This is a weak and difficult to predict problem. We expect it to become more reactive with more load (Thurs), and once triggered may cause large avalanches running into the lower elevations.

Use conservative route selection, choose moderate angled and supported terrain with low consequence.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 3

Wind Slabs

Fresh wind slabs can be expected with the new snow and strong forecasted winds.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Feb 9th, 2017 4:00PM