Avalanche Forecast

Issued: Apr 2nd, 2016 4:00PM

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

stephen holeczi, Parks Canada

Banff Yoho Kootenay.

Some cloud cover should keep the solar input at bay, but watch locally for sun affect as the danger rating can spike dramatically and rapidly. We are close to true spring conditions, so get up early and come home early.

Summary

Weather Forecast

Sunday calls for mainly cloudy conditions except in the East where the sun will poke through for periods of the day.Â Freezing levels to 2400m and mainly light Westerly winds.Â There could be some flurries along the divide.Â Monday looks like a few cm of snow with freezing levels to 2300m.

Snowpack Summary

After 3 hot days, expect surface crusts on all aspects (expect high due North aspects) with moist snow underneath. Crusts will rapidly break down with daytime heating or sun exposure. In many places the snowpack is sitting on a deep persistent of facets that has been avalanching to size 3.5 with solar heating over previous days.

Avalanche Summary

Less natural activity today due to moderate winds. Yesterday, numerous deep persistent avalanches to size 3 on many aspects, and loose wet avalanches to size 2.5 on solar aspects. On Thursday, there were solar induced natural avalanches in Kootenay to size 3.5 where the sun has been out all day. Many of these were stepping to ground.

Confidence

Timing or intensity of solar radiation is uncertain on Sunday

Problems

Deep Persistent Slabs

Deep facet layers remain weak & stressed by the recent heat and will take a bit of time to adjust. This layer will be harder to trigger due to the recent activity, but be cautious in thin snowpack areas.

Avoid slopes when the solar radiation is strong, especially if they have large cornices overhead.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 3

Loose Wet

If the sun comes out, the snow pack is warm and will rapidly deteriorate and expect slush style avalanches to be running in gullies, from cliffs and on steep slopes facing the sun or in below treeline terrain.

If triggered the loose wet sluffs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

Cornices

Cornices are large. Give them a wide berth on ridge crests, as they can pull back a long way when they fail and may trigger avalanches below. If you need to travel under cornices, move quickly and think twice if there is significant heating.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

2 - 3

Valid until: Apr 3rd, 2016 4:00PM