Avalanche Forecast

Issued: Feb 6th, 2016 4:28PM

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

Ruari Macfarlane, Parks Canada

Waterton Lakes.

High winds arrived on Friday & Saturday, but brought only a little new snow. Watch for avalanche hazard to increase rapidly with sustained above-freezing temperatures early next week.

Summary

Weather Forecast

Cloudy on Saturday with continued strong-extreme Westerly winds. These remain strong Sunday, easing to light through Monday. Sunday & Monday look mainly clear. Temperatures fall this afternoon, then rise slowly through Sunday, approaching zero late evening. By Monday, many forecast models predict temperatures well above freezing at most elevations.

Snowpack Summary

5-10cm of recent snow in higher terrain has formed Wind Slabs, which may be found in usually sheltered locations, due to extreme W winds Friday night. Buried below are older wind slabs, more difficult to trigger. Down 50 cm is a weak layer in isolated areas, and 1m deep is a faceting rain crust. Sensitivity of these will rise with temperatures.

Avalanche Summary

Several small Wind Slab avalanches were observed on Saturday.

Confidence

Freezing levels are uncertain

Problems

Wind Slabs

New snow and extreme Westerly winds have and built Wind Slabs in unusual areas: these may include lower than usual in start zones, and in typically wind-sheltered terrain.

Use ridges or ribs to avoid pockets of wind loaded snow.If triggered the wind slabs may step down to deeper layers resulting in large avalanches.

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

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

Deep Persistent Slabs

Facets sit atop at crust buried around a meter deep. This layer generally requires large triggers, but will increase in sensitivity during periods of warm temperatures. Another persistent weak layer still exists about 50cm deep in isolated areas

Use caution on wide-open slopes - these are the most suspect.Carefully evaluate big terrain features by digging and testing on adjacent, safe slopes.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Loose Wet

This problem is expected to develop early next week with warm temperatures. It may exist on all aspects, however solar aspects will be the most suspect.

Avoid ice climbs exposed to steep rocky terrain on solar aspects during the middle of the day.Watch for clues, like sluffing off of cliffs, that the snowpack is warming up.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Feb 9th, 2016 4:00PM