Avalanche Forecast

Issued: Dec 25th, 2013 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 and Wind Slabs.

snow safety, Parks Canada

Banff Yoho Kootenay.

The basal depth hoar can be heard jing, jing, jingling in your snow pit. Conservative terrain choices are important to stay safe when dealing with this overall weak snowpack. Happy holidays. SH

Summary

Weather Forecast

The very windy alpine conditions will continue Thurs and Fri. with strong to extreme westerlies. Light snow amounts of 5-10cm expected over the next 2 days and freezing levels to valley bottom.

Snowpack Summary

5-10cm of new snow in the W tapers to nothing in the E. A variety of surface weaknesses including widespread windslabs in the ALP and isolated surface hoar at TL & BTL sit on a generally weak snowpack. The real concern is the facet/depth hoar/crust combo at the base of the snowpack which been triggered by light loads recently and can't be trusted.

Avalanche Summary

A size 2.5 was observed 2 days ago on a N aspect of Mt. Fairview. It was initiated as a wind-induced spindrift avalanche which pulled out a slab that failed near the ground. This is indicative of the widespread basal weakness present in the snowpack.

Confidence

Due to the quality of field observations on Wednesday

Problems

Deep Persistent Slabs

Full depth, human triggered avalanches are likely in specific features. This basal crust/depth hoar problem will last for a while to come.

Avoid areas with overhead hazard.Avoid steep, open slopes.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

2 - 3

Wind Slabs

Windslabs are prevalent in many areas at upper elevations, and any new snow and wind will contribute to their formation. Once triggered in steeper terrain, these have been seen to trigger deeper releases on the basal weakness.

Be aware of the potential for full depth avalanches due to weak layers at the base of the snowpack.Use caution in lee areas in the alpine. Recent wind loading have created wind slabs.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Dec 26th, 2013 4:00PM