Avalanche Forecast

Issued: Feb 10th, 2017 4:00PM

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

snow safety, Parks Canada

Banff Yoho Kootenay.

Avoid all avalanche terrain until things improve! We expect natural avalanche activity to taper off by the end of Saturday, but the likelihood of human triggering will remain high for some time.

Summary

Weather Forecast

A strong Westerly flow will continue for the next couple of days with a few flurries on Saturday and a drying trend for Sunday. Alpine winds continue to be in the Moderate to Strong range with a dip in temperatures overnight Friday down to the low teens, and a gradual rise in temperatures over the next several days.Â

Snowpack Summary

10-25cm of new snow with extreme winds from the SW and warming temperatures, have created new snow slabs over a fundamentally weak snowpack comprised mostly of facets and depth hoar. Snowpack tests indicate failures, numerous avalanches have been observed, and we expect more avalanches on these weak facet layers over the next 24hrs.

Avalanche Summary

Numerous natural avalanches were observed and reported throughout the forecast region up to size 3 in the last 24hrs. These have been a mix of loose dry avalanches in steep gullies, wind loaded slopes in the alpine and at treeline, and deep persistent slabs triggered by the wind slabs and loose dry avalanches.

Confidence

Due to the number and quality of field observations

Problems

Wind Slabs

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

If triggered the storm/wind slabs may step down to deeper layers resulting in large avalanches.Avoid freshly wind loaded features.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Loose Dry

Wind loading has resulted in numerous loose dry avalanches over the last 24 hours out of steep cliffs and gullies. Ice climbers in particular should avoid any climbs in avalanche terrain until this activity dies down.

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

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Deep Persistent Slabs

The new snow has created a touchy slab over the weak facets at all elevations, resulting in many avalanches that could potentially run full path. Avoid avalanche terrain on Saturday and remember to watch out for overhead slopes and gullies.

Avoid all avalanche terrain.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

2 - 4

Valid until: Feb 11th, 2017 4:00PM