Avalanche Forecast

Issued: Feb 9th, 2017 4:00PM

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

grant statham, Parks Canada

Banff Yoho Kootenay.

A significant avalanche cycle is starting on Thursday night and will peak on Friday. Avoid avalanche terrain on Friday, and although things may improve slightly for the weekend - extreme winds will keep the avalanche danger high on Saturday.

Summary

Weather Forecast

A strong SW flow is driving moisture over the region and bringing extreme winds right through the weekend. Expect a storm total of 30 cm by Friday morning, along with winds in excess of 100 km/hr in alpine areas overnight Thursday. Temperatures are rising also, but look to remain below freezing along the Continental Divide areas through the storm.

Snowpack Summary

10cm of new snow over the past 24-hrs and another 20cm expected by Friday will be blown into deep windslabs by extreme winds from the SW on Thursday night. These new slabs overlie a fundamentally weak snowpack comprised mostly of facets and depth hoar. Snowpack tests indicate failures, and we expect action on these layers over the next 48-hrs.

Avalanche Summary

Poor visibility today, but during our field trip to Crowfoot Pass we could hear avalanches occurring in the cliffs overhead.

Confidence

Problems

Wind Slabs

Expect drifted snow to be deeper than 100 cm in leeward areas on Friday and very susceptible to human triggering. Give avalanche terrain a wide berth and remember that any fracture lines my extend further that you expect.

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

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 3

Deep Persistent Slabs

This problem is likely to "wake up" during this storm, resulting in large avalanches that could potentially run full path. Avoid avalanche terrain on Friday. and remember to watch out for overheard slopes and gullies.

Avoid all avalanche terrain.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

2 - 4

Valid until: Feb 10th, 2017 4:00PM