Avalanche Forecast

Issued: Nov 25th, 2018 4:17PM

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

Conrad Janzen, Parks Canada

Banff Yoho Kootenay.

The skiing has taken a bit of hit in many places as the snowpack continues to facet and weaken. Rocks/stumps are easier to hit as well. In steep terrain watch for stiffer slabs over the weak facets that could result in skier triggered avalanches.

Summary

Weather Forecast

Forecasts for Monday vary significantly from a trace of new snow to between 5-10 cm. It looks like winds will increase to the moderate range out of the SW and treeline temperatures will stay between -10 and -5 C.

Snowpack Summary

5-10 cm of recent snow sits over sun crust on steep south slopes or surface hoar on sheltered N aspects. Thin wind slabs exist in the alpine. The October 26 crust is generally found 10-30 cm above the ground with large facets growing both above and below it. The snowpack averages 40-85 cm at 2200m across the region and is weakening as it facets.

Avalanche Summary

Plenty of whumphfing on the October 26 crust and facet layer in the last several days. One explosive controlled size 2 failing on the Oct 26 crust was reported in the alpine at Lake Louise on Sunday. Ski cutting produced a thin new snow slab on a steep alpine S aspect at Sunshine Village on Sunday. No new natural avalanche activity observed.

Confidence

Due to the number and quality of field observations

Problems

Deep Persistent Slabs

Occasional reports continue of skier remote and explosive triggered slabs on the October 26 crust and facet layer. Avoid steep terrain where a stiffer, more cohesive slab exists over these weak, faceted crystals near the base of the snowpack.

Whumpfing is direct evidence of a buried instability.If you are increasing your exposure to avalanche terrain, do it gradually as you gather information.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Nov 26th, 2018 4:00PM