Avalanche Forecast

Issued: Apr 18th, 2017 8:12AM

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

ian gale, Parks Canada

Glacier.

If the sun comes out today expect the new storm snow to become more reactive and the low elevation snowpack to turn to mush.

Summary

Weather Forecast

Today will be cloudy with sunny periods and isolated flurries. Ridge top wind will be from the SW at 15-35kph and freezing levels will reach 1800m. The rest of the week continues to remain unsettled with cloudy skies, freezing levels between 1800-2100m and small amounts of daily precip.

Snowpack Summary

15cm of new snow fell overnight with freezing level around 1000m. Yesterday the surface snow was observed to be moist on all aspects to well into the alpine and previous SW winds created wind slabs on lee features & huge cornices at ridgetop. Isothermal snow can be found below TL. Cold, dry snow may be found on very high northerly slopes.

Avalanche Summary

A field team encountered touchy surface wind slabs on northerly lee aspects at 2200m. The 10-15cm soft slabs were easily failing with ski cuts and running fast on a temp crust. Yesterday sz 2.0 low elevation wet avalanches were observed likely due to rain & warm temps.

Confidence

Timing, track, or intensity of incoming weather system is uncertain

Problems

Storm 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.

Be cautious as you transition into wind affected terrain.Watch for shooting cracks or stiffer feeling snow. Avoid areas that appear wind loaded.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Loose Wet

Warm overnight temps have created a poor refreeze and new snow has fallen on a already warm snowpack. With warm temps forecast and potential for solar radiation, the snowpack at lower elevations will lose it's cohesion.

Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.Watch for clues, like sluffing off of cliffs, that the snowpack is warming up.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

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.

Stay well to the windward side of corniced ridges.Minimize exposure to overhead hazard from cornices.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

2 - 4

Valid until: Apr 19th, 2017 8:00AM