Avalanche Forecast

Issued: Mar 20th, 2015 4:00PM

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

conrad janzen, Parks Canada

Banff Yoho Kootenay.

The new snow has begun to improve ski conditions at treeline and above. Watch for wind slabs in specific terrain features and keep an eye on cornice development over the weekend. Travel remains a bit rugged at lower elevations.

Summary

Weather Forecast

Light snow and mild temperatures with moderate SW winds are forecast through Saturday. Sunday we expect a mix of sun and cloud with cooler temperatures. Monday and beyond look unsettled with occasional light precipitation.

Snowpack Summary

8cm of new snow at tree line and above on Friday with moderate SW winds and temperatures near 0`C. Wind slabs present in lee and open areas at tree line and above. The recent snow sits on a variety of surfaces and is generally bonding well. The base of the snowpack is made up of facets and depth hoar and remains weak. Below tree line snow is moist.

Avalanche Summary

Local ski areas were able to ski cut small wind slabs in immediate lees areas on Friday. This problem is expected to increase slightly over the next 36hrs as more snow arrives.

Confidence

Intensity of incoming weather systems is uncertain on Saturday

Problems

Wind Slabs

5-10cm of recent storm snow has formed wind slabs up to 35cm in the lee areas of alpine features. These will be sensitive to human triggering on features such as ridge crests and cross loaded gullies. Cornices are also becoming a concern.

Use caution in lee areas. Recent wind loading have created wind slabs.Be cautious as you transition into wind affected terrain.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Deep Persistent Slabs

The lower half of the snowpack is weak due to the presence of basal facets and depth hoar. This layer has been dormant lately but may become more sensitive with the forecasted new snow load, especially in thin areas.

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

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Mar 21st, 2015 4:00PM