Avalanche Forecast

Issued: Dec 6th, 2013 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 Persistent Slabs.

conrad janzen, Parks Canada

Banff Yoho Kootenay.

Cold temperatures continue to be the major factor affecting the snowpack today. The snowpack overall is relatively weak and shallow with a deep persistent basal weakness. Early season hazards such as stumps and rocks are near the surface.

Summary

Weather Forecast

The cold temperatures and clear skies will continue for the next couple days with only slightly warmer temperatures over the weekend. No significant snowfall is expected until the middle of next week however a small system may arrive from the North on Monday bringing cloudy skies and very light amounts of snow.

Snowpack Summary

Continuing cold temperatures means not much active is happening in the snowpack. The surface and basal layers will continue to facet. Snowpack depths at tree line are around 60-70cm.

Avalanche Summary

No new avalanche activity observed today on a flight over the main ranges to Lake O'Hara. A full depth size 2.5 release on a steep planar NW feature at 2400m on Copper Mtn was observed 2 days ago. Likely the northerly winds and cross loading across this slope with the coming of the arctic front was the trigger.

Confidence

Problems

Wind Slabs

Recent storm snow was moved around by northerly winds and isolated wind slabs can be found on all aspects at and above tree line. Use caution in steeper wind affected areas.

Be careful with wind loaded pockets while approaching and climbing ice routes.Stay off recent wind loaded areas until the slope has had a chance to stabilize.

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Persistent Slabs

The basal layers of depth hoar and/or the October melt freeze crust are the major weakness in the snowpack and any avalanche will likely fail on, or step down to these layers. Triggering on steep open slopes is still possible.

Avoid unsupported slopes.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

Unlikely - Possible

Expected Size

1 - 3

Valid until: Dec 7th, 2013 4:00PM