Avalanche Forecast

Issued: Feb 5th, 2017 9:49AM

The alpine rating is extreme, the treeline rating is extreme, and the below treeline rating is high. Known problems include Storm Slabs, Deep Persistent Slabs and Loose Dry.

jonas hoke, Parks Canada

Waterton Lakes.

New snow continues to pile up. Expect to see a natural avalanche cycle lasting through Monday.

Summary

Weather Forecast

Moist, mild Pacific air collides with a cold Arctic High. Forecasts predict anywhere from 40-140cm of snowfall by Monday evening. Alpine winds are mainly moderate SW. Temperatures will drop as the arctic air re-establishes itself Monday in to Tuesday, winds will remain light and variable at all but the upper elevations.

Snowpack Summary

Up to 80cms and counting (60-80cm more is forecast) with light-moderate wind, this overlies: wind-hardened snow exposed areas, near surface facets in sheltered areas, and a melt-freeze crust below 2000m on solar aspects. The lower snowpack facets remain as a persistent concern and have produced isolated Sudden results in snowpack tests.

Avalanche Summary

Nearby operations reported a widespread storm slab problem yesterday, which was easily triggered by skiers and explosives.

Confidence

Forecast snowfall amounts are uncertain

Problems

Storm Slabs

The new snow will require several days to settle and stabilize.Avoid all avalanche terrain.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Very Likely

Expected Size

2 - 3

Deep Persistent Slabs

Deeply buried Persistent weak layers from a cold winter have produced few results in recent testing, but are now being heavily loaded. In sheltered/windward terrain, this is the first large load on these layers. Avoid previously shallow areas.

If triggered the storm slabs may step down to deeper layers resulting in large avalanches.Be aware of the potential for wide propagations.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

3 - 4

Loose Dry

Loose Dry avalanches will fail naturally in steep areas.

The new snow will require several days to settle and stabilize.Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Very Likely

Expected Size

1 - 2

Valid until: Feb 8th, 2017 4:00PM