Register
Get forecast notifications
Create an account to receive email notifications when forecasts are published.
Login
Archived

Avalanche Forecast

Feb 4th, 2017–Feb 5th, 2017
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
3: Considerable
The avalanche danger rating below treeline will be considerable
Alpine
4: High
The avalanche danger rating in the alpine will be high
Treeline
4: High
The avalanche danger rating at treeline will be high
Below Treeline
3: Considerable
The avalanche danger rating below treeline will be considerable
Alpine
4: High
The avalanche danger rating in the alpine will be high
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
3: Considerable
The avalanche danger rating below treeline will be considerable

Regions: Kootenay Boundary.

Fresh storm slabs will become increasingly sensitive to human triggers as the snow load increases.

Confidence

Moderate - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

Saturday night: 15-20 cm new snow/ Moderate to strong, southwest winds/ Freezing level 800 m.Sunday: 0-5 cm new snow/ Light, southwest winds/ Freezing level 800 m.Sunday night: 15-20 cm new snow / Light to moderate southwest winds / Freezing levels dropping to valley bottoms.Monday: 20-25 cm new snow/ Light, southwest winds/ Freezing level valley bottom.Tuesday: 0-5 cm new snow/ Light, southwest winds/ Freezing level valley bottom.

Avalanche Summary

No new avalanche observations were reported on Friday. Fresh storm slabs will likely have a poor bond to the old snow surfaces and be reactive through the weekend, potentially stepping down and initiating deep persistent slabs.

Snowpack Summary

20-25 cm of new snow has buried a variety of old snow surfaces including stiff wind slab or wind effected snow at upper elevations, sun crust on steep southerly slopes and surface hoar in sheltered areas. Another 15-20 cm is expected by Sunday morning bringing storm totals to 35-45 cm. Below the surface, 50-65 cm of settled snow now sits above an interface that was buried in mid-January. The interface is composed of weak facets, surface hoar, and/or sun crusts and the strength of the bond is reportedly variable. Recent snowpack tests have shown sudden results on that interface. Areas with a shallower snowpack (less than 150 cm) have a generally weak snowpack structure with sugary facets near the ground. This includes shallow alpine slopes and most of the Rossland range. Smaller storm slab avalanches may step-down to these deeper weak layers, resulting in large, destructive avalanches.

Avalanche Problems

Storm Slabs

Touchy storm slabs becoming more likely to trigger.
Use conservative route selection, choose moderate angled and supported terrain with low consequence.Watch for signs of instability such as whumpfing, shotting cracks, or recent natural avalanching.Use small slopes with low consequence to test the bond of the new snow.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely

Expected Size: 1 - 2

Deep Persistent Slabs

Smaller storm slabs may step-down to deeper weak layers, resulting in large, destructive avalanches.
Be aware of the potential for full depth avalanches due to weak layers at the base of the snowpack.Dig down to find and test weak layers before committing to a line.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Unlikely - Possible

Expected Size: 2 - 3