Archived

Avalanche Forecast

Jan 19th, 2016–Jan 20th, 2016

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

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

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: Northwest Inland.

Wind slabs are lingering in the south of the region. Be cautious as you transition into wind affected terrain and watch for recently wind-loaded features.In the deeper snowfall areas in the north, watch for storm slabs over a layer of surface hoar.

Confidence

Low - Due to the number of field observations

Weather Forecast

A mix of sun and cloud is expected for Wednesday with the possibility of light flurries. Freezing levels are expected to be 500-700m and alpine winds should be mainly moderate from the southeast. A weak storm system is expected to bring 5-10cm of new snow on Thursday with freezing levels at 600-800m and strong southerly winds in the alpine. Unsettled conditions are expected for Friday as the storm moves off.

Avalanche Summary

On Monday, a small natural cornice release triggered a size 2.5 slab avalanche in the north of the region. Skiers also triggered a few slab avalanches size 1-2 in the north. All these avalanches released on the Jan 9 surface hoar layer down 30cm. Reports from Sunday include generally small skier triggered storm and wind slabs avalanches, some of which ran on the Jan 9 surface hoar. Skier triggered sluffs were also reported to run far on Sunday.

Snowpack Summary

The region has a mix of wind slabs and developing storm slabs. In higher snowpack areas in the northwest of the region, the storm slab has become reactive to human triggers. In most other areas the wind slabs are thin and stiff. Buried surface hoar is layered through the thin snowpack, and cool temperatures as well as limited loading have preserved these weak layers. The mid pack that was reported to be well settled may have now facetted in the shallower areas, and the deeper basal layers are almost certainly facetted and weak. We have not heard of any full depth releases on weak basal layers yet.

Avalanche Problems

Wind Slabs

Recently formed wind slabs have been reactive to human-triggering. In the north of the region, a more widespread storm slab problem may be developing over a layer of surface hoar.

Use ridges or ribs to avoid pockets of wind loaded snow. >Watch for signs of the development of a more widespread storm slab problem, especially in the north of the region. >Be cautious as you transition into wind affected terrain. >

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

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 3