Parks Canada Conrad Janzen, Parks Canada

Banff Yoho & Kootenay National Park Avalanche Forecast

Nov 24th, 2019 4:00PM

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

Natural avalanche activity will decrease on Monday but human triggering of wind slabs will remain likely. Use caution or avoid fresh wind loaded areas and narrow gullies until the new snow has had a chance to settle and bond.

Summary

Weather Forecast

Winds will stay out of the west but start to decrease on Monday to the moderate range. Temperatures will be a few degrees cooler than Sunday, with treeline temperatures between -5 and -10 C. No new snow is expected. Things continue to cool down and clear up on Tuesday.

Snowpack Summary

10-20 cm of new snow with strong W winds have formed new touchy wind slabs at ridge tops and in open alpine areas. The Nov 8 crust is down 20-30 cm and is present up to ~2400 m. The lower snowpack is a mix of facets and the Oct crusts. Snowpack depths at treeline range from 60-90 cm with up to 140 cm in lee areas.

Avalanche Summary

Sunday had numerous natural, skier triggered and explosive triggered small wind slabs up to size 2. These mostly occurred in lee areas near ridge tops and in the high alpine. Triggering these will remain likely into Monday.

Confidence

Wind effect is extremely variable

Problems

Wind Slabs

An icon showing Wind Slabs

Likelihood

Likely

Expected Size

1 - 2

Fresh wind slabs have formed in lee areas near ridge tops and in open alpine areas. Skier or climber triggering of these wind slabs will remain likely into Monday.

  • If triggered the wind slabs may step down to deeper layers resulting in large avalanches.
  • Use caution in lee areas. Recent wind loading have created wind slabs.

Aspects:

North, North East, East, South East, South.

Elevations:

Alpine, Treeline.

Deep Persistent Slabs

An icon showing Deep Persistent Slabs

Likelihood

Possible

Expected Size

1 - 2

The lower snowpack consists of weak facets and crusts. With the recent snow load there is potential for avalanches to step down to this deeper persistent layer.

  • Convex features and steep unsupported slopes will be most prone to triggering.

Aspects:

All aspects.

Elevations:

Alpine, Treeline.

Valid until: Nov 25th, 2019 4:00PM