Archived

Avalanche Forecast

Dec 9th, 2021–Dec 10th, 2021

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

Below Threshold

The avalanche danger rating below treeline will be below threshold

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

Below Threshold

The avalanche danger rating below treeline will be below threshold

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

Below Threshold

The avalanche danger rating below treeline will be below threshold

Regions: Yukon.

AM Update: Snowfall and wind have been much lighter than forecast. Pay attention to any changes in weather conditions and be ready to re-evaluate terrain choices.

Confidence

High - We have a good understanding of the snowpack structure and confidence in the weather forecast

Weather Forecast

Approaching storm should peak overnight but continue through much of Friday.

Thursday Overnight: South winds cranking up into the 60 to 110 km/hr range.

Friday: Strong to extreme south winds gradually lessening to moderate (approx 40 km/hr). Expect 10 to 20 cm of total storm snow. Temperatures around -10 C.

Saturday: Broken or overcast sky, light north east wind, a few flurries, and cooling temperatures nudging towards -20's C.

Sunday: Similar to Saturday only a few degrees cooler. Touching -25 C is possible.

Avalanche Summary

Our AvCan field team reported whumpfs and shooting cracks up to 10 m from thin snowpack areas in the Fraser Chutes on Wednesday. No new avalanches observed today (Thursday).

Snowpack Summary

Here's a picture of my mental map of the region's snowpack.

Terrain and Travel

Avoid areas with overhead hazard.
Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.
Avoid terrain traps such as gullies and cliffs where the consequence of any avalanche could be serious.
Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.

Avalanche Problems

Storm Slabs

There's a 25 to 40 cm thick blanket of snow, with more on the way. It's all available for the wind to move and build wind slabs. Watch for them on lee slopes behind ridges or in cross-loaded terrain behind rib or gully features. The best riding will be in the trees with some wind protection.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Almost Certain

Expected Size: 1.5 - 2.5

Deep Persistent Slabs

Whumpfing from thin snowpack areas in Fraser Chutes confirms weakness near the ground is real. The risk I picture is whumpfing from a thin rocky area and triggering a slope above you where the snowpack is 150 cm or more (but the weak layer is still way down near the ground).

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 2 - 3