Avalanche Forecast

Issued: Nov 27th, 2018 4:00PM

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

ian jackson, Parks Canada

Banff Yoho Kootenay.

Visibility was poor today, so limited observations on Tuesday. A little bit of new snow with some moderate SW winds has created some small reactive windslabs in the alpine.

Summary

Weather Forecast

A warm wet storm is hitting the coast, but we won't get much in the Rockies. We should see another 5-10 cm with mild temperatures by the end of day Thursday with moderate SW winds. Colder air is coming on Friday as temperatures drop to -15 to -20 and winds switch to the NW.

Snowpack Summary

Moderate SW winds and 5-10 cms of new snow has created windslabs in the alpine. These sit on sun crust on steep south and surface hoar on sheltered N aspects. The Oct 26 crust is 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

Sunshine Village ski patrol was reporting thin soft windslabs in immediate lees on Tuesday. These were touchy, but small and low consequence at this time. No other avalanches observed or reported, but visibility was limited.

Confidence

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.

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

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Wind Slabs

A little bit of new snow and moderate SW winds have created thin windslabs in immediate lees. These are small, but could be consequential in steep or exposed terrain.

Use caution in lee areas. Recent wind loading have created wind slabs.Be careful with wind loaded pockets while approaching and climbing ice routes.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 1.5

Valid until: Nov 28th, 2018 4:00PM