Avalanche Forecast

Issued: Jan 26th, 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.

tim haggarty, Parks Canada

Banff Yoho Kootenay.

Strong winds are expected Sunday morning. Give overhead avalanche terrain a wide berth until winds settle back down later in day.

Summary

Weather Forecast

Freezing levels Saturday reached 2300m with moderate West winds. Overnight, alpine winds are forecast to increase to strong to extreme as a cold front passes bringing some precip and a cooling trend begins. Midday Sunday should bring and end to the winds as temperatures drop further. Clearing overnight into Monday.

Snowpack Summary

10-20cm of snow over the last week over isolated suncrusts and surface hoar. Widespread wind effect in the alpine creeping into treeline with current winds. 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

No new avalanches observed or reported today.

Confidence

Wind speed and direction is uncertain on Sunday

Problems

Deep Persistent Slabs

The weak Oct.26 facets and depth hoar at the base of the snowpack have a significant slab (50-130cm thick) sitting above them. The likelihood of triggering this layer has decreased, but if it does get triggered, the avalanche will be large in size.

Avoid thin, rocky or unsupported slopes.Be aware of the potential for full depth avalanches due to weak layers at the base of the snowpack.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 3

Wind Slabs

Thin wind slabs are currently stubborn and a bit old however with strong winds in the forecast, the potential for these, or cornice features to fail will remain for Sunday.

If triggered the wind slabs may step down to deeper layers resulting in large avalanches.Minimize overhead exposure during periods of heavy loading from wind.

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 1.5

Valid until: Jan 27th, 2019 4:00PM