Avalanche Forecast

Issued: Apr 22nd, 2014 4:30PM

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

brian webster, Parks Canada

Banff Yoho Kootenay.

Spring time conditions exist. Pay attention to how strong the overnight freeze is and how quickly it warms during the day. Start your tours early and be home before it warms up.

Summary

Weather Forecast

Tonight brings scattered flurries and freezing levels near valley bottom. Wednesday brings a mix of sun and cloud with freezing levels near 2000 m. Thursday freezing levels may rise to 2400 m.

Snowpack Summary

Warm day time temperature and very mild overnight freezes are the current conditions. Moist snow in afternoon on solar aspects up to ridgetops and to 2400 m on polar aspects. Temperature crusts breaking down by mid-morning.

Avalanche Summary

Kootenay Park had a loose snow avalanche cycle yesterday afternoon. Surface loose snow avalanches up to Class 2 running out of steep rocky terrain. Debris generally running to top of runouts. No slab avalanches observed.

Confidence

Freezing levels are uncertain on Wednesday

Problems

Loose Wet

Loose wet avalanches are possible in the afternoon as a result of day time heating. Monitor how thick the crusts are and how quickly they break down during the day.

Avoid avalanche terrain during periods of rain.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

Deep Persistent Slabs

Although unlikely it is still possible to trigger a slab avalanche on one of the deep persistent layers. Skier triggering of this layer is more likely in shallow snowpack areas.

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

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Cornices

Cornices weaken with day time heating. Field observations show numerous recent cornice collapses.

Do not travel on slopes that are exposed to cornices overhead.

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

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Apr 23rd, 2014 4:00PM