Avalanche Forecast

Issued: Apr 8th, 2017 6:37PM

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 Wind Slabs.

snow safety, Parks Canada

Banff Yoho Kootenay.

The deep slab instabilities still persist in the snowpack. Spring condition have yet to arrive in the alpine. Its still winter up high.

Summary

Weather Forecast

Convective flurries are expected Sunday, these pulses can move in quickly and bring in some accumulation. Temps will remain cooler with freezing levels reaching valley bottom tonight and climbing to 1600 by tomorrow afternoon.

Snowpack Summary

Over 25cm of new snow Friday above 2000m. Light to moderate winds loaded lees, developing small wind slabs. 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

Some small slab releases to size 1.5 out of the new windslab.Â reports were skier triggered and specific to loaded lees slopes.

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

Wind Slabs

Newly formed windslabs developed saturday morning, Load was specific to lees features and up to 40cm thick. Reports of several skier triggered slabs to size 1.5 Saturday.

Aspects: North, North East, East.

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Apr 9th, 2017 4:00PM