Avalanche Forecast

Issued: Feb 9th, 2018 4:00PM

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

snow safety, Parks Canada

Banff Yoho Kootenay.

http://www.pc.gc.ca/apps/scond/cond_e.asp?oid=30728&opark=100092Please continue to avoid avalanche terrain. While natural avalanche activity is beginning to taper, human triggering will continue to be very touchy. Solar releases can be expected from rocky terrain.

Summary

Weather Forecast

A few days without precipitation and moderately cold temperatures are forecast. Sunny skies may produce solar releases from rocky areas. The crystal ball says more snow on Tuesday.

Snowpack Summary

Thursdays storm dropped 30 - 50cm with variable winds. This combined with other recent snow has overloaded the 3 main mid pack concerns which are the Jan 16th, Jan 6th, and Dec.15 weak layers. These are a mix of facets, crusts and surface hoar and can be found 70cm to over 150cm deep in the snowpack and are currently producing very large results.

Avalanche Summary

The avalanche cycle seems to be tapering but large, natural events to size 3.5 were noted today. Human triggering continues to be reported. Avalanche control today produced many large avalanches over paths that had been controlled very recently.

Confidence

Problems

Persistent Slabs

Three weak layers exist in the mid snowpack: Jan 16, Jan 6, and Dec 15. All are a mix of sun crust, surface hoar and facets depending on the aspect and elevation. These layers are very sensitive to triggering both naturally and by human triggering.

Avoid all avalanche terrain.Watch for whumpfing, hollow sounds, shooting cracks or recent avalanches.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

2 - 4

Storm Slabs

There are storm slabs up to 1m thick on many aspects and elevations from the big storm on Thursday. These will be highly sensitive to triggering and once initiated, can step down to the deeper persistent layers causing very large avalanches.

If triggered the storm slabs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2.5

Valid until: Feb 10th, 2018 4:00PM