Archived

Avalanche Forecast

Dec 6th, 2021–Dec 7th, 2021

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

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

3: Considerable

The avalanche danger rating at treeline will be considerable

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

Regions: Vancouver Island.

Rapid warming will likely further destabilize storm slabs over a slippery crust. As the storm slab problem gets trickier, the easy solution is to choose more conservative terrain.

Confidence

Low - Uncertainty is due to how the snowpack will react to the forecast weather.

Weather Forecast

Monday night: A trace of new snow. Moderate northwest wind. Freezing level rising to 2000 m.

Tuesday: Flurries 5-10 cm. Moderate southwest wind building to strong in the afternoon. Treeline high temperature around +1. Freezing level trending down 2000-1500 m.

Wednesday: Overnight snow 15-20 cm. Strong northwest wind. Treeline high temperatures around -5. Freezing level 700 m.

Thursday: A mix of sun and cloud. Light northwest wind. Treeline high temperatures around -5. Freezing level 800 m.

Avalanche Summary

No recent reports.

Snowpack Summary

A spike in freezing levels overnight will promote rapid settlement in 20-40 cm of recent snow, precariously perched on a slippery crust. In the short term, rapid settlement is a destabilizing process but over they day, the warm temperatures may help the snow bond to the crust.

Underneath this snow, the 5-10 cm thick crust is reportedly supportive to skis but not boots or sleds. Faceting has been observed on its underside.

Recent indications of the region's surviving snowpack suggest alpine depths around 150 cm, depth tapering dramatically with elevation to about 30-60 cm at treeline. Below treeline is largely bare.

Terrain and Travel

Use conservative route selection. Choose simple, low-angle, well-supported terrain with no overhead hazard.
Use small low consequence slopes to test the bond of the new snow.
Keep in mind the crust offers an excellent bed surface for avalanches.

Avalanche Problems

Storm Slabs

Rapid settlement due to an overnight spike in temperature will likely further destabilize storm slabs, precariously perched on a slick crust. Over the day, however, the warm temperatures may even facilitate bonding at the snow/crust interface. You can dig down to investigate.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely - Very Likely

Expected Size: 1.5 - 2.5