Avalanche Forecast

Issued: Dec 21st, 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.

Grant Statham, Parks Canada

Banff Yoho Kootenay.

A weak, early season snowpack dominates the forecast area, and will for the foreseeable future. It's possible to trigger full depth avalanches right now. The snow quality is excellent, with 20 cm of dry powder on most slopes at treeline. GS

Summary

Weather Forecast

A NW flow persists over the region with no significant systems expected in the next 24-hours. A trace of snow is expected by Sunday morning, followed by clearing and light NW winds with temperatures ranging from -10 to -20.

Snowpack Summary

20 cm of loose, dry snow sits on top of a generally weak snowpack. The total snowpack depths range from 60-100 cm at treeline, with the deeper snow located on the western side of the forecast region. In the Lake Louise to Bow Summit region, the lower half of the snowpack is weak depth hoar and avalanches are likely in steep, open slopes.

Avalanche Summary

No new avalanches were observed today.

Confidence

Problems

Deep Persistent Slabs

The snowpack is weak and should not be trusted. This is classic Rocky Mountain conditions, and is not expected to change in the near future. Settle in to this reality, and keep the terrain mellow over the next few days.

Be aware of the potential for full depth avalanches due to weak layers at the base of the snowpack.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

2 - 3

Wind Slabs

Wind slabs exits in open areas, but may be hidden beneath the soft surface snow. Enter leeward or cross loaded areas carefully, and from the side to check for the presence of surface slabs before committing.

Use caution in lee areas in the alpine. Recent wind loading have created wind slabs.The recent snow may now be hiding windslabs that were easily visible before the snow fell.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Dec 22nd, 2013 4:00PM