Avalanche Forecast

Issued: Jan 25th, 2018 4:00PM

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

snow safety, Parks Canada

Little Yoho.

An intense storm overnight has tipped the scales and overloaded the weak layers in Little Yoho. A natural avalanche cycle to size 3 occurred Thursday. This will ease with minimal precip Friday and Sat, but will pick up again with a big storm Sunday

Summary

Weather Forecast

The SW flow continues, and we will see continued light snowfall amounts friday and saturday with a bigger looking storm coming in on Sunday. Approximately 3-5 cms per day with a drop in temperatures and winds. Sundays storm will be the one to watch and will likely trigger another avalanche cycle if it materializes.

Snowpack Summary

20 cm of new snow overnight makes 70 cm of storm snow over the last 9 days. 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 40cm; Jan 6 down 55cm; Dec15 down 70 cm giving easy-mod test results

Avalanche Summary

Last nights snow triggered a natural avalanche cycle in Little Yoho on Thursday. Avalanches up to size 3 ran on Mt Dennis including the ice climbs Carlsberg Column, Extra Lite, Super Bok and Heineken Hall. A close call with a group of climbers who were leading the crux pitch of Carlsberg when an avalanche poured over there heads.

Confidence

Due to the number of field observations

Problems

Wind Slabs

20 cm of new snow overnight and strong winds triggered a natural avalanche cycle today. Many avalanches failed as windslabs and stepped down to the deeper persistent weak layers.

Avoid all avalanche terrain.Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.

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

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 2.5

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. Recent loading has overloaded these layers and we are seeing avalanche running far.

Avoid all avalanche terrain.It is a good time to stay within the boundaries of a ski resort.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Valid until: Jan 26th, 2018 4:00PM