Avalanche Forecast

Issued: Feb 4th, 2016 5:26PM

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

Ruari Macfarlane, Parks Canada

Waterton Lakes.

New snowfall with high winds on Friday night will create Wind Slabs. Watch the freezing levels - the new load, and a rise in temperatures on Sunday, may also be enough to tickle a Deeply buried Persistent layer back to life.

Summary

Weather Forecast

Flurries tomorrow, followed by upto 10cm of snowfall on Friday night, then a partial clearing late on Saturday morning. Strong Westerlies rise steadily to almost 100kph Friday night, then ease through Saturday afternoon. Sunday looks dry with Moderate Westerlies. Warm temperatures, cooling Friday night, then rising to near freezing on Sunday.

Snowpack Summary

5-10cm of new snow at upper elevations has formed soft Wind Slabs, lee to Moderate Westerly winds. These are currently stubborn to human triggering. Buried below are older wind slabs, more difficult to trigger. Down 1m is a faceting rain crust. Though mainly requiring large triggers, any avalanche triggered on this would be large & destructive.

Avalanche Summary

Numerous small loose dry avalanches observed today from very steep terrain. One Size one Wind Slab observed today, at 2000m on an open, NE facing slope. On Sunday, a large, Deep Persistent slab avalanche was noted on the same slope... these are occurring on an occasional, but semi-regular, basis. They are large, and difficult to predict.

Confidence

Forecast snowfall amounts are uncertain on Saturday

Problems

Wind Slabs

Stubborn Wind Slabs exist lee to Westerly winds, and will increase in size and sensitivity by Saturday.

If triggered the wind slabs may step down to deeper layers resulting in large avalanches.Use caution in lee areas. Wind loading will create slabs.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Deep Persistent Slabs

Facets atop a deeply buried crust produced large avalanches in recent weeks, and are giving Sudden results in tests. The strength of this layer is highly variable across terrain, so a conservative approach to big terrain is crucial.

Be aware of the potential for large, deep avalanches.Use caution on wide - open slopes - these are the most suspect.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 3

Loose Dry

Small loose dry avalanches are running naturally out of steep terrain.

Minimize overhead exposure during periods of heavy loading from new snow, wind.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 1

Valid until: Feb 7th, 2016 4:00PM