Avalanche Forecast

Issued: Jan 7th, 2018 4:00PM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is low. Known problems include Wind Slabs and Loose Dry.

conrad janzen, Parks Canada

Banff Yoho Kootenay.

With steady light snow over the next few days the hazard will rise very gradually. Stay alert to these changes, watch for clues like sluffing, and continually monitor the reactivity of the surface snow over the buried facets and surface hoar.

Summary

Weather Forecast

The forecast is for cloudy skies with small amounts of snow, light to moderate West winds, and temperatures fairly steady in the -5 to -10'C range for the next three days. Total accumulations may reach 15-20cm in Western areas, but we will likely only see 5-10cm in the Eastern parts of our forecast region.

Snowpack Summary

15-40 cm of snow now sits over the Dec 15 layer of surface hoar or sun crust, and is beginning to develop soft slab properties with the warmer temperatures and wind. Below this the snowpack is heavily faceted with remnants of older crust's still lingering throughout. In steep gullies, loose faceted surface snow continues to be a significant concern

Avalanche Summary

A small skier triggered loose dry avalanche at treeline, and some thin small wind slabs in the alpine were reported on Sunday by the local ski areas. There have also been several small skier accidental avalanches involving thin wind slabs in the alpine during the past several days and reports of the December 15 layer slowly becoming more reactive.

Confidence

Intensity of incoming weather systems is uncertain on Tuesday

Problems

Wind Slabs

Recent snow is being moved around by the SW winds and forming thin wind slabs in immediate lee areas. These slabs can fail on the either the weak facets or the Dec 15 layer, and have been triggered by climbers and skiers in the last few days.

Use caution in lee areas. Recent wind loading has created wind slabs.Watch for surface cracking and stiffer surface layers of snow. Avoid wind loaded terrain.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Loose Dry

Loose dry surface snow avalanches will continue to be a problem in steep rocky areas and gullies until the facets round out and begin to bond better.

The volume of sluffing could knock you over; choose your climb carefully and belay when exposed.On steep slopes, pull over periodically or cut into a new line to manage sluffing.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Jan 8th, 2018 4:00PM