Avalanche Forecast

Issued: Nov 14th, 2018 4:00PM

The alpine rating is considerable, the treeline rating is moderate, and the below treeline rating is below threshold. Known problems include Wind Slabs and Deep Persistent Slabs.

grant statham, Parks Canada

Banff Yoho Kootenay.

The storm arrived mid-day Wednesday and deposited 15 cm by mid-afternoon. Forecast models are now calling for a total of 30-40 cm by the end of the day on Thursday. Watch out for fresh windslabs and overhead hazard at treeline.

Summary

Weather Forecast

A strong westerly flow is bringing moisture and wind across the region through until early Friday morning. Forecast models are calling for another 20-25 cm on Thursday for a total of 35-40 through the whole storm. Expect strong Westerly winds at ridge crests and temperatures steady around -5. Clearing and cold air for the weekend.

Snowpack Summary

Windslabs forming in alpine and treeline areas starting late Wednesday with drifts up to 30cm deep in the lee. These slabs will continue to build overnight and should be easy to trigger by Thursday. This new snow overlies a weak, facetted base which produces test failures on the Oct 26 melt-freeze crust 30-40 cm above the ground.

Avalanche Summary

No new avalanches reported today. Sunshine Village reported that the windslabs were just starting to become stiff enough to create a soft slab late in the afternoon.

Confidence

Forecast snowfall amounts are uncertain on Thursday

Problems

Wind Slabs

Strong winds have created windslabs in leeward areas that are becoming stiff enough for a human trigger. Avoid all steep leeward avalanche terrain on Thursday.

Use caution in lee areas. Recent wind loading has created wind slabs.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Deep Persistent Slabs

This problem is found in most north facing (shaded) terrain up to 2800m, and will become more reactive as the storm deposits more load. Recommend avoiding all steep alpine terrain for the next few days.

If you are increasing your exposure to avalanche terrain, do it gradually as you gather information.Whumpfing is direct evidence of a buried instability.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Nov 15th, 2018 4:00PM