Avalanche Forecast

Issued: Feb 6th, 2017 4:00PM

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

grant statham, Parks Canada

Banff Yoho Kootenay.

Avalanche control is planned for the Sunshine road on Tuesday, so the ice climbing routes are closed. We are right on the edge of the big storm in the east, but did not get the same huge dump as they did in K-Country. Expect a big cycle this weekend.

Summary

Weather Forecast

This storm is ending on Monday night. Tuesday will remain cold with mostly light NE winds except at higher elevations where the winds will be stronger (brrr). Temperatures will remain in the -20 range for Tuesday. The upper level flow shifts back to SW later this week, and Thursday we will see the start of warming, winds and more precipitation.

Snowpack Summary

The past 3-day storm has deposited 25cm at SSV, 16cm at Lake Louise, 12cm at Mt. Stanley and 35cm in Kootenay Park. Wind effects have generally been light, but we expect soft slab formation in alpine areas where N winds have created reverse loading. All of this sits on a very weak snowpack structure. We are on the cusp of a major avalanche cycle.

Avalanche Summary

Small, explosive triggered slab avalanches reported below treeline at Sunshine Village. Road patrol down Kootenay Park showed no new avalanche activity.

Confidence

Due to the number of field observations

Problems

Deep Persistent Slabs

This is a weak and difficult to predict problem. We expect it to become more reactive now with more load, and once triggered may cause large avalanches running into the lower elevations. Avoid all big avalanche terrain.

Use conservative route selection, choose moderate angled and supported terrain with low consequence.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 3

Wind Slabs

We suspect this problem exists at the higher elevations, but do not yet have a real observation of it. With the current fresh snow available for transport, only a very small increase in winds speed will create wind slabs.

Keep an eye out for reverse loading created by an upslope storm.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Likely

Expected Size

1 - 2

Valid until: Feb 7th, 2017 4:00PM