Avalanche Forecast

Issued: Apr 13th, 2017 4:00PM

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

snow safety, Parks Canada

Banff Yoho Kootenay.

Great ski quality to be had right now. Just remember that there are still weak basal facets deep in the snowpack, and it is a slow start to spring. Ease into bigger terrain and avoid slopes under large cornices.

Summary

Weather Forecast

Snow tapering off in all regions for Friday with light winds and freezing levels down to valley bottom overnight and up to 1900m with mainly cloudy skies.Â A cooling trend is expected through the weekend.

Snowpack Summary

Small amounts of snow this past week have added up to about 20-40cm. On solar aspects, this new snow is sitting over a couple of sun crusts into the alpine, and small storm slabs 20cm thick have formed in specific alpine features. At tree line and above a 120cm+ firm slab with few weaknesses overlies weaker basal facets in much of the region.

Avalanche Summary

No new avalanches observed or reported on Thursday.

Confidence

Due to the number of field observations

Problems

Deep Persistent Slabs

The snowpack is gaining strength, but the weak basal facets continue to produce sudden collapse results and can produce large avalanches with large triggers. Stick to planar, supported slopes with a deeper snowpack if entering steep terrain.

Pay attention to overhead hazards like cornices which could easily trigger deep slabs.Be aware of thin areas that may propogate to deeper instabilites.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 4

Cornices

April is cornice failure season, and we continue to get reports of cornices failing and triggering deep slabs. Mature cornices can also break much further back than you expect, so give them a wide margin when traveling on ridges.

Stay well to the windward side of corniced ridges.Do not travel on slopes that are exposed to cornices overhead.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 3

Storm Slabs

These are small in size and will be short in duration as a problem, but storm slabs were being triggered in numerous alpine locations Thursday. On solar aspects these may be sitting on a sun crust.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Apr 14th, 2017 4:00PM