Archived

Avalanche Forecast

Dec 9th, 2017–Dec 10th, 2017

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

1: Low

The avalanche danger rating at treeline will be low

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

1: Low

The avalanche danger rating at treeline will be low

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Regions: Lizard-Flathead.

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

Confidence

Moderate - Timing or intensity of solar radiation is uncertain

Weather Forecast

Expect mainly clear skies and a temperature inversion for the forecast period. Alpine temperatures are expected to reach 2 degrees on Sunday and then climb to 5 degrees on Monday and Tuesday. Ridgetop winds are forecast to be moderate from the southwest on Sunday, becoming light on Monday and Tuesday.

Avalanche Summary

On Friday a few stiff wind slabs to size 1.5 were explosive-triggered at treeline. 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 some surfaces over the past few days. In shaded higher elevation terrain where surface snow remained cold and unconsolidated, recent shifting winds redistributed loose snow forming stiff wind slabs on a wide range of aspects at treeline and above. Roughly 30-60 cm below the surface you'll likely find a hard crust that was buried on November 26. This crust is approximately 30 cm thick and extends from 1600 m to mountain top on all aspects. Below this crust, the snowpack is moist to ground. Average snowpack depths at treeline elevations in the region range from 80-120 cm.

Avalanche 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.

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

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 Sunday - especially in steeper terrain.

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

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

Elevations: Alpine.

Likelihood: Possible

Expected Size: 1 - 2