Avalanche Forecast

Issued: Jan 12th, 2014 4:51PM

The alpine rating is high, the treeline rating is high, and the below treeline rating is considerable. Known problems include Deep Persistent Slabs and Storm Slabs.

Grant Statham, Parks Canada

Banff Yoho Kootenay.

The avalanche cycle continues with many natural, human and explosive triggered avalanches occurring everywhere. Avoid avalanche terrain; this situation is very touchy and several close calls were had today. More snow and wind expected for Monday.

Summary

Weather Forecast

Another 10-15cm is forecast on Sunday night, tapering my mid-day Monday. Extreme wind warnings are in effect, with gusts up to 110 km/hr expected. Temperatures will remain between -5 and -10. The longer range forecast shows this storm system to dissipate by Tuesday, leading to a drier week ahead.

Snowpack Summary

45cm of storm snow has fallen over the last few days, combined with very strong winds. Deep storm slabs have formed from new snow and wind loading; in excess of 100 cm in leeward areas. These slab are overloading a weak, facetted snowpack. WIth another 15 cm expected by mid-day Monday, this critical situation will persist for a few more days.

Avalanche Summary

Large natural and explosive controlled avalanches continue to occur in many areas, including slopes adjacent to the ski area boundaries. Numerous human triggered avalanches adjacent to the ski areas, including Maintenance Cliffs near Lake Louise and a very close call on Wawa Ridge. Avoid all avalanche starting zones on Monday.

Confidence

Problems

Deep Persistent Slabs

The current avalanche cycle is overloading the entire snowpack and many deep avalanches have been observed sliding on the ground. Fracture lines in some areas greater than 150cm deep. The situation is very touchy; avoid all avalanche terrain.

Be aware of the potential for wide propagations.Be aware of the potential for full depth avalanches due to deeply buried weak layers.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

2 - 3

Storm Slabs

45 cm storm snow and extreme winds have created deep storm slabs that can easily be triggered by humans. Extreme winds on Monday night will only add to this problem.. Avoid all avalanche terrain until this cycle subsides.

Use caution in lee areas in the alpine and treeline. Recent storm snow has formed touchy slabs.Avoid freshly wind loaded features.

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

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 3

Valid until: Jan 13th, 2014 4:00PM