Avalanche Forecast

Issued: Apr 6th, 2017 4:00PM

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

Lisa Paulson, Parks Canada

Banff Yoho Kootenay.

Another warm day Friday before we see a cooling trend through the weekend. Travel at treeline and below will not be great over the next few days.

Summary

Weather Forecast

A series of warm low pressure systems continue to move across BC and AB. Showers and flurries forecasted for Thursday evening followed by freezing levels dipping down to 1600 m. Friday it will be cloudy and warm with more precipitation in the evening.Â Expect rain in the valley bottom and snow above 2000m may accumulate 10cm before it stops.

Snowpack Summary

A settled, mostly dry snowpack exists on shaded aspects above 2300m. On other aspects and below 2300m, expect morning crust and wet snow by mid-day. The base of the snowpack continues to be unstable with a layer of facets failing approximately 60cm above the ground. For this reason, most avalanche prone slopes are out unless they have already slid.

Avalanche Summary

No new avalanches were observed or reported today.Â On the Wapta, reports of several recent cornice failures triggering deep slabs on the slopes below.

Confidence

Problems

Deep Persistent Slabs

The snowpack is generally unstable, despite the strong feel of the surface layers. This warm-up is again testing the snowpack and we expect increased avalanche activity. Patience is a virtue with this kind of problem.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 4

Cornices

April is cornice season, and we are getting regular reports of cornices failing and triggering deep slabs. Mature cornices can propagate much further than you expect, so give them a wide margin when traveling on ridges. Travel early.

Avoid steep slopes below cornices.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Loose Wet

Wet snow flows like water in gullies during warm spring days, and the next few days we expect wet snow avalanches to be common in gully areas at and below treeline. Ice climbers - avoid steep low elevation gullies.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Apr 7th, 2017 4:00PM