Avalanche Forecast

Issued: Feb 12th, 2017 4:05PM

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

aaron beardmore, Parks Canada

Banff Yoho Kootenay.

Extensive wind transport across the forecast region has re-loaded wind slabs that were touchy to begin with. Conservative terrain choices will be important over the next few days in order to avoid encounters with avalanches.

Summary

Weather Forecast

Above zero temperatures are forecasted to start on Monday. Thankfully the wind will die down to the moderate range at the 3000m level. All of the aforementioned conditions will be accompanied by clearing skies and lack of precipitation.

Snowpack Summary

30-60cm of new snow in the past 10 days with extreme winds from the SW have created new slabs over a weak snow pack comprised mostly of facets, buried wind layers, and depth hoar. We expect more avalanches on these weak facet layers over the next while as the snowpack adjusts to the load.

Avalanche Summary

Strong to extreme wind has produced another avalanche cycle. A size 3 avalanche ran over the Bourgeau Left ice climb going full path. Also, a size 3 near Bow summit was observed by forecasters this morning. Photo here.

Confidence

Due to the number and quality of field observations on Sunday

Problems

Wind Slabs

Strong to extreme wind on Sunday has created fresh wind-slabs that are ripe for human triggering. Give avalanche terrain a wide berth as 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: North, North East, East, South East, South, South West.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

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, of which there have been numerous examples.

Be aware of the potential for wide propagations.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

2 - 4

Valid until: Feb 13th, 2017 4:00PM