Avalanche Forecast

Issued: Mar 17th, 2016 4:00PM

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

snow safety, Parks Canada

Banff Yoho Kootenay.

Pay attention to solar warming as the sun comes out over the next few days. Lots of big avalanches have been triggered with avalanche control showing that the deeper layers are still active.

Summary

Weather Forecast

Friday and Saturday should be warm and sunny with cold overnight temperatures.Â

Snowpack Summary

The snowpack is complex right now. 30-70 cm of new snow sits on crusts below 1800m and on W through E aspects into the alpine. This has been reactive with explosives in many areas recently. On darker aspects, the new snow is bonding better, but the lower snowpack is still facetted and weak, with many avalanches stepping down to near the ground.

Avalanche Summary

Recent avalanche control along the highways produced large, deep avalanches. Additionally, cornices were large and easily triggered.

Confidence

Problems

Deep Persistent Slabs

The mid-pack facets remain weak, especially in thin or rocky areas. Avoid steep or unsupported terrain, and watch for signs of instability such as whumpfing and cracking.

Avoid steep convexities or areas with a thin or variable snowpack.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 3

Persistent Slabs

Now that the sun is higher in the sky, buried suncrust becomes more of a problem. Presently there are several crusts buried on S through E aspects, with 30-70 cm overlying them. This problem is most significant in the south Kootenay region.

Dig down to find and test weak layers before committing to a line.

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 3

Cornices

Cornices are large and fragile right now. Numerous cornices have been triggered by explosives and skiers in the last few days stepping down into deeper layers on the slopes below. Heads up as the sun destabilizes them further over the next few days.

Give cornices a wide berth when travelling on or below ridges.Avoid slopes when the solar radiation is strong, especially if they have large cornices overhead.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Mar 18th, 2016 4:00PM