Avalanche Forecast

Issued: Apr 16th, 2013 4:38PM

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

tim haggarty, Parks Canada

Waterton Lakes.

Sunshine and warmer weather will have a significant impact on the large amounts of fresh snow we have had and may affect cornices as well. The hazard will be lower in the morning if things refreeze but watch carefully for the effects of heating.

Summary

Weather Forecast

Wed mainly sunny freezing level near 1800m winds shifting to SE.Thursday sunny periods with a freezing level near 2000m.Friday Cloudy freezing level near 2000m winds SW

Snowpack Summary

65cm sits above the April 7 crust at treeline and 60cm sits above the April 11 crust on all aspects to 2000m and solar aspects to ridge lines. Moderate winds today affecting ridgeline and exposed areas creating soft slabs. Crusts continue to gain strength but moist snow remains beneath them on solar aspects.

Avalanche Summary

There has been widespread loose dry avalanches running naturally out of extreme terrain or sluffing with skiers in steep terrain. These events have been relatively small but some have run a long distance in continuously steep terrain sometimes gouging down to the crusts. With increased wind today there was noticeably less of this activity

Confidence

Freezing levels are uncertain

Problems

Loose Dry

New snow from recent and incoming storms will fail easily in steep terrain with skier traffic and naturally from extreme terrain. With underlying crusts these events may travel a long distance and gain mass. Manage your group carefully.

On steep slopes, pull over periodically or cut into a new line to manage sluffing.Be very cautious with gully features.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Storm Slabs

With mild spring temperatures and variable winds, new snow quickly settles into a slab. With sun and temperature crusts as a firm bed surface the bond of this new snow should be examined carefully before committing to steep or unsupported terrain.

Make observations and assess conditions continually as you travel.Avoid freshly wind loaded features.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Loose Wet

The sun will come out Wednesday and quickly affect solar slopes and cornices. Rising temperatures will affect even shaded slopes Thursday and Friday. Be cautious with moist or wet snow especially if it penetrates as far as the crusts.

Be alert to conditions that change with elevation.Pay attention to overhead hazards like cornices.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Apr 19th, 2013 4:00PM