Avalanche Forecast

Issued: Apr 7th, 2017 4:00PM

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

snow safety, Parks Canada

Banff Yoho Kootenay.

There is still uncertainty with the deep persistent problem. Conservative decision-making is key, as we can still trigger large avalanches.

Summary

Weather Forecast

The majority of the precipitation will tapper Friday night with temperatures expected to cool and freezing levels remaining below 1700m on Saturday. Unsettled weather will continue through the weekend with mostly cloudy skies and periods of precipitation but no significant accumulation.

Snowpack Summary

Over 10cm of new snow Friday above 2000m, wind transport was isolated to ridge crest in the alpine. Lower elevation snowpack is in a melt freeze cycle, recovering overnight and deteriorating through the day. The base of the snowpack remains unstable with a layer of facets failing approximately 60cm above the ground, releasing deep slabs.

Avalanche Summary

No new avalanches were observed or reported today.

Confidence

Problems

Deep Persistent Slabs

The snowpack is generally unstable, despite the strong feel of the surface layers. This layer remains reactive in snowpack test and can produced large avalanches. Patience is a virtue with this kind of problem.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

2 - 4

Cornices

April is cornice season, and we are getting regular reports of cornices failing and triggering deep slabs. Mature cornices can propagate much further than you expect, so give them a wide margin when traveling on ridges.

Avoid steep slopes below cornices.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Loose Wet

Wet snow flows like water in gullies during warm days, this problem becomes more predominant with daytime warming and rain. Steep gully features and thin rocky areas are the spots to avoid when this problems reactivity increases through the day.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Apr 8th, 2017 4:00PM