Avalanche Forecast

Issued: Nov 18th, 2015 4:00PM

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

stephen holeczi, Parks Canada

Banff Yoho Kootenay.

What a start to the ski season! Forecasters almost think they live somewhere else. Give the snowpack some time to settle to the new load. It's been a lot of snow in a short period of time. SH

Summary

Weather Forecast

Cooler temperatures for Thursday and Friday with valley temps between -10 to -12 and alpine temperatures in the -18 to -25 range. Only trace amounts of snow are expected over the next 2-3 days with light to moderate W to NW winds.

Snowpack Summary

Essentially 2 major snowfall events in the past week has created the snowpack. The latest one from Tues threw down 30-50cm low density snow in most areas. There is a fairly supportive midpack, but inconsistent results are still being found within the storm snow, and in some circumstances, near the ground. HS at treeline is well over a meter.

Avalanche Summary

Avalanche control in Yoho, Kootenay and Sunshine produced mixed results. Most produced sluffing, or wind slabs to size 2.5. There were 2 examples of avalanches stepping to near ground layers, both on high/smooth alpine terrain where facets are likely more prominent. Lake Louise ski hill also used many explosives and had minimal results.

Confidence

Due to the number of field observations on Thursday

Problems

Wind Slabs

Previous strong winds have redistributed the loose snow into leeward areas where wind slabs should be expected within the upper snowpack. This was evident during avalanche control Wednesday. So far, this doesn't appear to be widespread.

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

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

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

1 - 3

Loose Dry

Wind will be the key Thursday, especially for ice climbers in gullies. Watch if the wind picks up, there's lots of loose snow available for sluffing.

The volume of sluffing could knock you over; choose your climb carefully and belay when exposed.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Nov 19th, 2015 4:00PM