Avalanche Forecast

Issued: Dec 8th, 2017 4:27PM

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

cgarritty, Avalanche Canada

Lizard-Flathead.

Avalanche danger is tightly linked to solar exposure and warming. Look to shaded aspects to find the best snow and safest riding.

Summary

Confidence

Moderate -

Weather Forecast

Saturday: Mainly sunny with valley cloud due to lingering temperature inversion. Light southwest winds. Freezing level to 3500 metres with alpine temperatures around +3. Cooler at lower elevations.Sunday: Mainly cloudy. Light west winds. Freezing level to 3500 metres with alpine temperatures around +5. Cooler at lower elevations.Monday: Mainly sunny with lingering valley cloud. Light southwest winds. Freezing level to 3500 metres with alpine temperatures around +6. Cooler at lower elevations.

Avalanche Summary

Reports from Tuesday included several observations of wind slabs releasing to Size 2 in the Fernie area. These were mainly triggered with explosives but one Size 1.5 slab did release with skier traffic. Looking forward, we should see a gradually diminishing potential for wind slab releases as warm daytime temperatures and overnight cooling promote bonding in the upper snowpack. Please submit your observations to the Mountain Information Network (MIN).

Snowpack Summary

Solar and temperature crusts are expected to have formed on the surface at higher elevations over the past two days. Below the surface, recent shifting winds redistributed loose snow at higher elevations, crossloading and forming wind slabs on a wide range of aspects at treeline and above. Below this wind effect, roughly 30-60 cm of storm snow is expected to be bonding well to the underlying crust that was buried on November 26. This crust is approximately 30 cm thick and extends from 1600 m to mountain top elevations on all aspects. Below this capping crust, the snowpack is moist to ground. Average snowpack depths at treeline elevations in the region range from 80-120 cm.

Problems

Wind Slabs

A recent wind shift from southwest to north means that wind slabs now exist on a wide range of aspects at higher elevations. Be especially cautious of reverse loaded or cross-loaded slopes that see sun exposure.

Be careful with wind loaded areas, especially near ridge crests and roll-overs.Use ridges or ribs to avoid pockets of wind loaded snow.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Loose Wet

Warm, sun-exposed slopes could continue to produce wet loose avalanches either naturally or with rider triggers on Saturday - especially in steeper terrain. This problem may expand to northerly aspects as warming persists.

Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.Be cautious of sluffing in steep terrain, particularly where the debris flows into terrain traps.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Dec 9th, 2017 2:00PM