Avalanche Forecast

Issued: Dec 13th, 2015 4:00PM

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

Aaron Beardmore, Parks Canada

Banff Yoho Kootenay.

Forecasters are still trying to determine where the surface hoar exits. Thus far sheltered locations between 1700m and 2150m is where it is being found.

Summary

Weather Forecast

We expect to see a few cm's of snow and increasing SW winds into Sunday. Temperatures will be slightly warmer ranging from -2 to -10'C.

Snowpack Summary

In sheltered terrain between 1700 and 2150m, a 30-40 cm soft slab sits over the December 3rd surface hoar. This layer continues to produce whumphs and easy shears in many locations, especially in areas to the West with more snow. No other significant shears have been observed. In the alpine isolated wind slabs exist in immediate lee areas.

Avalanche Summary

No new avalanches observed today in our forecast area. Ski cutting produced some small slabs on the Dec 3 SH in steep terrain near the Simpson slide paths today. These slabs were ski cut in the immediate lee.

Confidence

Problems

Persistent Slabs

A 30-40cm soft slab sits over the Dec 3 surface hoar in an elevation band between 1700 and 2150m. Continue to treat all steep open slopes below treeline with suspicion until you can rule out this weak layer.

Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Wind Slabs

With increasing winds Saturday night, continue to watch for wind slabs in typically suspicious areas: leeward and cross loaded slopes or slopes near ridge crests.

Use caution in lee areas. Recent wind loading have created wind slabs.

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Dec 14th, 2015 4:00PM