Avalanche Forecast

Issued: Feb 18th, 2018 4:00PM

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

aaron beardmore, Parks Canada

Banff Yoho Kootenay.

While avalanche activity is tapering, give wide margin to steep, open and planar features.

Summary

Weather Forecast

Cold temperatures will persist in the forecast region for another few days. Expect lows in the -20 range. Very light precip is expected over the next 3 days, 2-5cm, which is not enough to effect the danger ratings. Wind velocity will be reasonable, generally light to moderate from the N-NW.

Snowpack Summary

Windslabs are common in open areas in the alpine, however the cold temps are making them considerably less touchy. A deep slab overlies midpack weaknesses of surface hoar, crusts, and facets. The depth of these slabs varies from 75 cm to 150 cm. These layers have been producing very large avalanches over the past week.

Avalanche Summary

No new avalanches were reported or observed today. Natural activity has been tapering off, but potential still exists.

Confidence

Due to the number of field observations on Sunday

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.

Use caution on open slopes and convex rolls Avoid steep convexities or areas with a thin or variable snowpack.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

2 - 3.5

Wind Slabs

Hard wind slabs exist in the alpine lees, however recent cold temps will likely induce a sluggish/slow behavior if triggered.

Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Feb 19th, 2018 4:00PM