Avalanche Forecast

Issued: Jan 24th, 2018 4:00PM

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

grant statham, Parks Canada

Banff Yoho Kootenay.

Continual snowfall, cool temps and light winds are making excellent ski conditions. The snowpack is adjusting well to the additional snow and conditions are good - but with three weak layers in the upper snowpack, we are waiting for a tipping point.

Summary

Weather Forecast

Continued snowfall expected through Thursday with another 10-15 on the ground by the end of the day Thursday. Temperatures will remain cool and winds moderate from the SW.Â Basically the same weather pattern will persist for the next few days.

Snowpack Summary

50cm of snow has fallen in small increments over the past 8-days creating a lot of loose snow on the surface. Alpine winds have distributed this into leeward areas but only at the highest elevations. Three persistent weak layers lurk in the upper half of the snowpack: Jan 16 down 25cm; Jan 6 down 40cm; Dec15 down 55 cm giving easy-mod test results.

Avalanche Summary

No new avalanches reported or observed, but people continue to get lots of whumphing and settlement cracks - a definite indication of instability. But . . . no significant avalanches.

Confidence

Problems

Wind Slabs

With up to 60cm snow over the past 8-days there is plenty of loose snow available to be blown into windslabs which should be anticipated in alpine areas near ridge crests. These windslabs should be easy to trigger on skis.

Use caution in lee areas. Recent wind loading have created wind slabs.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Persistent Slabs

There are 3 weak layers in the upper snowpack: Jan 16, Jan 6, and Dec. 15. All are a mix of sun crust, surface hoar and facets depending on your aspect and elevation. Whumphing is occurring on these layers daily and step down avalanches are possible

Use conservative route selection, choose supported terrain with low consequence.Watch for whumpfing, hollow sounds, shooting cracks or recent avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2.5

Valid until: Jan 25th, 2018 4:00PM