Avalanche Forecast

Issued: Dec 11th, 2017 4:51PM

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

jmcbride, Avalanche Canada

Kootenay Boundary.

Pockets of windslab can be found near ridge top on open east aspects. Meanwhile a spring-like, melt-freeze cycle is underway on solar aspects at all elevations, watch for moist or wet snow once the crust breaks down.

Summary

Confidence

High - The weather pattern is stable

Weather Forecast

TUESDAY: Cloudy with sunny periods. Ridge winds light to moderate from the west. Alpine temperature -5. Freezing level near 1000m. Alpine inversion.WEDNESDAY: Cloudy with sunny periods. Ridge winds light from the northwest. Alpine temperature -3. Freezing level near 1000m.THURSDAY: Mainly cloudy. Ridge winds light from the northwest. Alpine temperature -3. Freezing level near 1000m. Alpine inversion.

Avalanche Summary

Small loose dry avalanches were observed from skier traffic in steep terrain on Saturday. Small wind slabs were released on Friday by a skier and explosives in alpine lee features. Small loose wet avalanches were observed on steep south-facing slopes on Thursday.

Snowpack Summary

On southerly aspects, warm daytime temperatures have melted the snow surface resulting in crust formation overnight. These crusts will likely breakdown quickly with sunny weather and warm temperatures expected to continue for the next few days. In shaded areas and on northerly aspects the surface consists of surface hoar up to 30 mm with faceted snow in the top 20 cm. The late-November crust is now buried 30-50 cm and is 15-25 cm thick. Recent snowpack tests have produced hard, resistant compression test results within the layers of crust. Below this layer the lower snowpack is strong and well settled.

Problems

Wind Slabs

Previous winds have produced pockets of wind slabs in lee features. These sit above the late-November crust.

Avoid wind-loaded pockets near ridges.

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Loose Wet

Warm air temperatures and clear skies have produced spring-like conditions on steep solar aspects. Loose wet avalanches may begin small but could step down to deeper crust layers.

Use caution above cliffs and terrain traps, where small avalanches may have severe consequences.Avoid sunny slopes when the solar radiation is strong, especially if the snow is moist or wet.

Aspects: North, North East, East.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Dec 12th, 2017 2:00PM