Avalanche Forecast

Issued: Mar 16th, 2017 4:00PM

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

stephen holeczi, Parks Canada

Banff Yoho Kootenay.

Avoid all avalanche terrain and the runouts of any avalanche path.

Summary

Weather Forecast

Freezing level to valley bottom Thursday night and a break from the storm. Winds will be in the moderate range. Another significant storm arrived Saturday morning with 30mm expected, alpine winds to 100kmh and freezing levels to 1900-2000m .

Snowpack Summary

30-60cm Thursday and moderate to strong winds have continued to build significant load over a fundamentally weak snowpack. The mix of previous rain, warm temperatures, and this new snow is overloading buried storm and windslabs, as well as the weak basal facet layers.

Avalanche Summary

A historic avalanche cycle is underway, with avalanches up to size 3.5 being widespread. Some are reaching maximal runouts, including onto trails in simple terrain. Avoid all avalanche terrain .

Confidence

Problems

Deep Persistent Slabs

The entire snowpack is built upon a structurally weak base, which has been overloaded by new snow and previous rain. Large deep persistent slabs have been observed and are running well into avalanche runouts.

Be aware of thin areas that may propogate to deeper instabilites.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Very Likely - Certain

Expected Size

3 - 4

Wind Slabs

Wind slabs over 1m deep exist at higher elevations, and in wind effected areas near treeline. This slab reacts easily to tests and continues to produce avalanches

Be aware of the potential for wide propagations.

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

Elevations: Alpine, Treeline.

Likelihood

Very Likely

Expected Size

1 - 3

Loose Dry

In the short term with this much snow hanging around sluffing in steep terrain and gullies will be occurring.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Very Likely - Certain

Expected Size

1 - 2

Valid until: Mar 17th, 2017 4:00PM