Avalanche Forecast

Issued: Jan 22nd, 2019 4:00PM

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

aaron beardmore, Parks Canada

Banff Yoho Kootenay.

Remain conservative in thin snowpack areas. Human triggering is still a real possibility. Today's forecast produced with help of Canmore Collegiate High school students ZZ, COC, ZH.

Summary

Weather Forecast

Seasonal temperatures a very light snowfall amounts are forecasted for the next 3 days. Wind will remain in the light to moderate range from the W.

Snowpack Summary

5-15 cm of snow sits over the Jan 17 layer of surface hoar, or sun crust. Thin wind slabs can be found in alpine lee areas from strong SW winds on Saturday. Of greatest concern are the weak facets and depth hoar at the base of the snowpack. In thinner snowpack areas with less than 150 cm of snow, triggering a slab on these facets is more likely.

Avalanche Summary

Little natural avalanche activity over the last week. However, one size 2 avalanche was observed today on Little Jimmy Simpson but it appeared to be greater than 3 days old.

Confidence

Due to the number of field observations on Tuesday

Problems

Deep Persistent Slabs

Weak facets and depth hoar at the base of the snowpack have a significant slab (50-130cm thick) sitting above them. While natural avalanche activity has decreased, human triggering of this layer is still possible, especially in thin snowpack areas.

Be aware of the potential for full depth avalanches due to weak layers at the base of the snowpack.Be aware of the potential for wide propagations which could result in large avalanches.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1.5 - 3

Wind Slabs

Southwest winds in the moderate to strong range have created thin, soft wind slabs in the alpine 10 to 20 cm deep. Use caution in lee areas.

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

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 1.5

Valid until: Jan 23rd, 2019 4:00PM