Avalanche Forecast

Issued: Feb 11th, 2014 4:00PM

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

Grant Statham, Parks Canada

Banff Yoho Kootenay.

The drought is over . . . and so is the Low danger! Snowfall amounts are building by about 10-15 cm per day this week, burying a dangerous layer of surface hoar and then accumulating a slab above it. Time to change our habits from the last few weeks.

Summary

Weather Forecast

At last the weather pattern has changed and we are into a NW flow, which has warmed up the air and finally brought some new snow.Â Expect another 5-10 cm on Wednesday, then another 10-15 for Thursday. Temperatures will be from -10 to -13 with strong wind gusts. Perfect for burying the weak layers . . .

Snowpack Summary

5-15 cm of new snow overlies a series of weak layers (surface hoar, facets and suncrust) formed from the past three weeks of cold, dry weather. As of today, this new snow had been blown into thin, soft slabs in specific areas above treeline. With additional snow forecast over the next few days, expect the soft slabs to increase in depth and size.

Avalanche Summary

Several soft windslabs 10-15 cm deep have been ski cut in windloaded areas above treeline. Avalanche activity is expected to increase on Wednesday and Thursday with the additional new snow.

Confidence

Forecast snowfall amounts are uncertain on Wednesday

Problems

Wind Slabs

By Wednesday there may be up to 25 cm of new snow being blown into fresh windslabs. Fresh slabs like this are touchy, and in places their depth may exceed 50 cm. Be very careful in all windloaded areas, and looks for clues and cracking under foot.

Be careful with wind loaded pockets while approaching and climbing ice routes.Avoid freshly wind loaded features.

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

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 2

Deep Persistent Slabs

This problem exists in the eastern side of the forecast region (Lake Louise area), and will remain dormant on Wednesday. More snow is needed to re-awaken these facets. Forecasters will be monitoring this problem closely as this week's storm develops.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely

Expected Size

1 - 2

Valid until: Feb 12th, 2014 4:00PM