Avalanche Forecast

Issued: Apr 17th, 2017 8:12AM

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

Parks Canada ian gale, Parks Canada

Touchy wind slabs are sensitive to human triggering in the Alpine. Down in the valley, warm overnight temps means the surface crust will break down quickly and hazard will rise as a result.

Summary

Weather Forecast

Mainly cloudy today, with 2-5 cm forecast in the alpine and potential for rain showers late in the afternoon at lower elevations. Ridge top wind will be from the SW at 10-25kph with freezing levels rising to 1800m. Tuesday will remain unsettled with some snowfall and freezing levels hovering around 1800m, this weather pattern continues to Thursday.

Snowpack Summary

10-20cm of new snow in the last 48 hrs. Moderate SW winds at tree-line and alpine have formed wind slabs on lee features & huge cornices at ridgetop. These slabs sit on a temp crust that extends to ridgetop. Cold, dry snow can be found on high northerly slopes while solar aspects become moist with sunshine & isothermal snow can be found below TL.

Avalanche Summary

A field team encountered touchy surface wind slabs in northerly lee aspects at 2200m. The 10-15cm soft slabs were easily failing with ski cuts and running fast on a temp crust. This layer was observed to be still reactive yesterday in the Asulkan valley. Late last week avalanches to size 3.5 were observed, likely cornice triggered.

Confidence

Freezing levels are uncertain

Problems

Wind Slabs

An icon showing Wind Slabs
Touchy surface slabs are sensitive to human triggering in wind-exposed alpine and tree-line areas. These sit on sun or temp crusts, depending on the aspect which exists well into the alpine.
Watch for shooting cracks or stiffer feeling snow. Avoid areas that appear wind loaded.Be cautious as you transition into wind affected terrain.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Cornices

An icon showing Cornices
The cornices are as big as they are going to get. Predicting their failure is tricky, but daytime warming or direct sun will weaken them. They have triggered some very large natural avalanches in and near Rogers Pass recently.
Minimize exposure to overhead hazard from cornices.Stay well to the windward side of corniced ridges.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

2 - 4

Loose Wet

An icon showing Loose Wet
Warm overnight temps have created a poor refreeze. With yesterdays warm temps(+9 at valley bottom) and freezing level predicted to go up to 1800m expect isothermal weak snow below treeline.
Watch for clues, like sluffing off of cliffs, that the snowpack is warming up. Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Apr 18th, 2017 8:00AM