Archived

Avalanche Forecast

Dec 15th, 2024–Dec 16th, 2024

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

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

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Regions: Banff, Banff Yoho Kootenay, East Side 93N, Field, Kootenay, LLSA, Lake Louise, Little Yoho, Sunshine, West Side 93N.

Although avalanche activity on the deep persistent layer has tapered over the last few days, it is still possible to trigger this layer (see avalanche table).

Confidence

Moderate

Avalanche Summary

Ski hills reported several small soft wind slabs in immediate alpine lees.
Of note, a group of climbers triggered and got caught in a size two slab that initiated on the deep persistent layer near the ground. This was on the approach to the climb C-Train (above Bow Lake). Climbers self rescued.

Snowpack Summary

5-10 cm recent snow with moderate southerly winds have scoured some alpine areas, and created isolated small wind-slabs in alpine lees. The mid and lower pack is faceted and weak east of the divide, and more settled in western regions. Weak interfaces exist down 20-40 on a facets/suncrust layer, and near the ground on the deep persistent layer (Nov 9 and Oct 20 interfaces). Snowpack depths at tree-line is about 60 cm in eastern areas and 100 cm west of the divide.

Weather Summary

Monday: Mixed sun and cloud forecasted. Valley bottom high temperature of -8 and ridgetop highs of -15. Winds SW in the light range.

Increasing cloud and light flurries along the Divide forecasted for Tuesday

Terrain and Travel Advice

Avoid thin areas like rocky outcrops where you're most likely to trigger avalanches on deep weak layers.
Watch for newly formed and reactive wind slabs as you transition into wind-affected terrain.

Avalanche Problems

Deep Persistent Slabs

Two weak layers near the base of the snowpack (Oct 20 and Nov 9) are producing slab avalanches down about 60-100 cm. Any areas with a stiffer slab over the mid pack facets have the potential to step down to these layers. Areas of most concern are steep, thin, wind affected spots.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 1.5 - 2.5

Wind Slabs

Previous SW/W winds have created small wind slabs in lee features of the alpine. Pay attention to wind loading as you transition to alpine terrain.

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

Elevations: Alpine.

Likelihood: Unlikely - Possible

Expected Size: 1 - 1.5