Avalanche Forecast

Issued: Apr 11th, 2016 4:20PM

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

brian webster, Parks Canada

Banff Yoho Kootenay.

Travel conditions should be good early in the day, but plan to start early and be down early before it gets too warm. Enjoy the spring skiing conditions!

Summary

Weather Forecast

Monday night will see a light freeze followed by another warm day on Tuesday with freezing levels around 2400 m. Wednesday will see a slight cooling trend and maybe some light flurries.

Snowpack Summary

A weak freeze overnight created supportive crusts that were breaking down by the late morning. Below the crust isothermal snow was found up to treeline on all aspects, and in thin alpine areas on S aspects. N aspects in the high alpine are more winter like. In many places the upper snowpack sits on a weaker deep persistent layer of rounding facets.

Avalanche Summary

Report of a skier triggered size 3 slab avalanche on the Corral 3 slide path near Lake Louise on Sunday, April 10. This was a NE aspect at 2400m and was triggered at 2:00 pmExplosive control on Saturday during the heat of the afternoon was able to produce several 2.5-3 loose wet avalanches out of steep treeline terrain in the Kootenay region.

Confidence

Problems

Loose Wet

All avalanche terrain should be avoided later in the day when the crust on top of the snowpack breaks down due to daytime heating. We expect this to occur mostly at lower elevations and on sun exposed alpine slopes. Start early and finish early!

Travel early on frozen crusts before the heat of the day.Watch for clues, like sluffing off of cliffs, that the snowpack is warming up.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Deep Persistent Slabs

Deep facet layers remain weak especially in thin snowpack areas and may be triggered during the hotter parts of the day.

Travel early before the heat of the day, and avoid big slopes in the afternoon.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Cornices

We have seen numerous cornice failures in the past week during periods of warm temperatures. Some of these have triggered large slabs on the slopes below. Minimize your time under cornices at this time of the year, especially later in the day.

Even small cornice falls may trigger larger avalanches.Cornices become weak with daytime heating, so travel early on exposed slopes.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Apr 12th, 2016 4:00PM