Avalanche Forecast

Issued: Dec 4th, 2018 4:00PM

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

Aaron Beardmore, Parks Canada

Banff Yoho Kootenay.

Little change. By definition the danger is low but there have been isolated skier remote avalanches in steep alpine terrain over the past several days. Conditions are good but its not open season. The snowpack continues to weaken with colder temps.

Summary

Weather Forecast

The benign weather pattern is staying with us for a few more days yet. Wind will remain light from the W/NW. The temperature may dip down to the -20 range Wednesday.

Snowpack Summary

Nil precip in last 24 hours. 5-10 cm of recent snow has been redistributed into thin wind slabs in immediate lee areas at treeline and above. The October 26th crust/facet layer is ~30 cm above ground. Snow depths range from 50-85 cm at 2000 m. In many areas the entire snowpack is faceting and becoming quite weak.

Avalanche Summary

No new natural avalanches observed today. There have been a few skier remote avalanches in the past several days, size 1.5-ish, in isolated locations where a hard slab was sitting over the weak basal facets. Some small loose dry sluffs have also been reported in steep alpine terrain.

Confidence

Due to the quality of field observations on Tuesday

Problems

Deep Persistent Slabs

It is still possible to trigger this layer but it will be in isolated, steep spots and often adjacent to thin rocky areas. Be cautious in steep terrain where a stiffer, more cohesive slab exists over the weak faceted snow at the base of the snowpack.

Whumpfing is direct evidence of a buried instability.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1.5 - 2

Valid until: Dec 5th, 2018 4:00PM