Avalanche Forecast

Issued: Feb 5th, 2017 4:00PM

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

aaron beardmore, Parks Canada

Banff Yoho Kootenay.

Storm slabs are expected to become touchy with additional snow on Sunday and Monday.

Summary

Weather Forecast

The storm will persist a bit longer. The forecast region is expecting up to another 10cm overnight, perhaps less in Western areas. Additionally, the temperature is going to dive down to -30 tomorrow, and creep back up later in the week. The wind will be variable in direction into the moderate range through Tuesday.

Snowpack Summary

Storm snow amounts are 10 to 30cm. This sits on harder wind pressed surfaces from previous strong W/SW winds at treeline and above. Surface hoar may be found buried in sheltered locations. Generally the midpack is weak at TL and above, and the entire snowpack is weak BTL. Near the divide, deeper snow-packs are a bit stronger and more supportive.

Avalanche Summary

Some small size 1 avalanches were reported on Mt. Dennis (Dennis 1 slide path) and from the Lake Louise ski area.

Confidence

Forecast snowfall amounts are uncertain on Monday

Problems

Deep Persistent Slabs

The snowpack is weak. Slopes where a slab sits over the deeper weak layers should be treated as suspect. Increasing load and further slab development will make these slabs more sensitive Monday and Tuesday.

Be aware of thin areas that may propogate to deeper instabilites.Use conservative route selection, choose moderate angled and supported terrain with low consequence.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 3

Storm Slabs

Small in size currently, watch locally for their formation and the bed surface they are lying on. There are wind layers, facets, surface hoar and sun crust depending on location.

Keep an eye out for reverse loading created by an upslope storm.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Feb 6th, 2017 4:00PM