Avalanche Forecast

Issued: Feb 7th, 2016 4:00PM

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

aaron beardmore, Parks Canada

Banff Yoho Kootenay.

The temperature will rise significantly, peaking on Tuesday. Windslabs remain very touchy. Wind-back aggressive terrain choices until we are through the warming period.

Summary

Weather Forecast

A warming trend will influence the region starting tomorrow and peaking on Tuesday with the freezing level potentially rising to 3200m. This will be accompanied by clear skies. Expect intense solar radiation during this period as well. This weather pattern will elevate the danger rating significantly.

Snowpack Summary

Wind slabs exist in the alpine and at tree line that are easy to trigger. The Jan 6 surface hoar/facet/sun crust layer, down 40-100cm, is becoming less reactive to skier triggering, however sudden collapse results persist on the Jan 6 and Dec 3 layers. Isolated whumphing on mid-pack facets/surface hoar have been observed this past week.

Avalanche Summary

We received a reliable report that two of the Healy Creek slide paths went size 3 sometime yesterday during or after the storm. Debris came within 50m of the trail in both occasions. Additionally, visitor safety staff observed a size 2.5 avalanche in the Mt. Whymper slide paths on highway 93S, it ran for approx 700m.

Confidence

Freezing levels are uncertain on Tuesday

Problems

Wind Slabs

New snow and very strong wind on Saturday have created touchy wind slabs in the alpine.

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

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Persistent Slabs

An average of 40-80 cm overlies the Jan 6 layer of surface hoar, facets and sun crust. Test results on this layer show it has become stubborn to trigger, but potential for wide propagation remains. The new snow will increase the likelihood of this.

Avoid open slopes and convex rolls where buried surface hoar may be preserved.Use careful route-finding and stick to moderate slope angles with low consequences

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 3

Valid until: Feb 8th, 2016 4:00PM