Avalanche Forecast

Issued: Dec 19th, 2015 4:11PM

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

snow safety, Parks Canada

Banff Yoho Kootenay.

New windslabs have formed in the alpine. Concern remains for the Dec 3rd persistent weak layer, dig frequently to check for presence of this spotty spotty surface hoar problem and keep a watchful eye on the character of the slab above it.

Summary

Weather Forecast

Westerly flow will bring light amounts of precip under mainly cloudy skies with light to moderate winds over the forecast period. Expect 10cm total through Monday as temps hover around -10C for daily highs at treeline. Winds should shift to a NW flow and bring some clearing beyond Monday after a system passes to the south of the forecast region

Snowpack Summary

Around 10cm of new snow now brings the faceted slab over the Dec 3 Surface Hoar to 30 to 50cm. While significant shears persist on this layer in isolated, shaded and sheltered areas from 1700m to 2150m, this problem has not been responsible for much activity and the potential for triggering is diminishing as the slab above it loses strength.

Avalanche Summary

A few reports of loose dry and windslab activity out of alpine terrain. Recent snowfall has combined with moderate W and SW winds creating isolated fresh slabs in alpine terrain.

Confidence

Due to the number of field observations

Problems

Persistent Slabs

A 30-50cm slab sits over the Dec 3 surface hoar that can be found in isolated areas between 1700 and 2150m. While this slab has facetted out in many areas, be cautious in aggressive terrain or in wind affected areas where the slab may retain strength

Avoid unsupported slopes.Dig down to find and test weak layers before committing to a line.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Wind Slabs

New isolated slabs are forming in alpine terrain

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

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Dec 20th, 2015 4:00PM