Avalanche Forecast

Issued: Feb 14th, 2018 4:12PM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is considerable. Known problems include Persistent Slabs and Wind Slabs.

Lisa Paulson, Parks Canada

Banff Yoho Kootenay.

Avalanche conditions continue to be very tricky. The snowpack is dangerous and avoiding avalanche terrain is important right now. Avalanches have been occurring in low angled terrain. Incremental loading will keep the hazard elevated.

Summary

Weather Forecast

Expect some flurries and the temperatures to drop the Arctic air pushes into the East side of the Rockies Tuesday night with light Northerly winds. On Thursday, temperatures will be around -15C and we will return to a Westerly flow with light flurries may resume Thursday evening.

Snowpack Summary

Strong SW winds in the past 48 hrs created widespread wind effect and hard windslabs at treeline and above. The upper half of the snowpack is a dense slab overlying three weak layers (Jan 16, Jan 6, & Dec 15) that are a mix of facets, crusts and surface hoar down 75-125cm in the snowpack. These layers have been producing very large avalanches.

Avalanche Summary

No new avalanches were observed or reported today - but we continue to see evidence of the large avalanches that occurred over the past few days. Today on Hector Shoulder trees we could see several deep fractures some of which occurred on low angle terrain.

Confidence

Problems

Persistent Slabs

A 100-125cm dense slab of January storm snow overlies three weak layers in the mid snowpack: Jan 16, Jan 6, and Dec 15. All are a mix of sun crust, surface hoar and facets depending on the aspect and elevation. These layers could easily be triggered.

Avoid all avalanche terrain.Be wary of slopes that did not previously avalanche.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

2 - 3.5

Wind Slabs

Strong winds last Tuesday night created widespread wind effect in most areas above treeline. Hard wind slabs exist in the alpine lees.

If triggered the wind slabs may step down to deeper layers resulting in large avalanches.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Feb 15th, 2018 4:00PM