Avalanche Forecast

Issued: Jan 6th, 2015 4:00PM

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

grant statham, Parks Canada

Banff Yoho Kootenay.

Avalanche control is planned for Wednesday, please avoid skiing and climbing on Mt. Field, Mt. Stephen, Mt. Bosworth, Mt. Whymper and the Simpson paths (previously known as the Vermillion paths).

Summary

Weather Forecast

NW flow aloft continues, and this moist air is colliding with cold arctic air somewhere over the Rockies. The majority of the precipitation from this storm is now over with only trace amounts expected overnight and tomorrow, but strong upper level winds and warming temperatures are expected for Wednesday.

Snowpack Summary

13 cm of snow in the last 24 hours brings the total storm snow since Jan 2 up to 30 cm. This storm snow remains mostly unconsolidated and has not yet formed into a cohesive slab except above 2500 m. Widespread cracking and whumphing observed today, and as soon as the surface snow forms a slab it will be easy to trigger.

Avalanche Summary

Several avalanches observed in the Field area, including one that ran over the ice climb Pilsner Pillar and another one from the Mt. Stephen cliffs that put 2.5 meters of debris on the railroad. Very limited observations from field teams and the ski areas today due to poor visibility.

Confidence

Problems

Storm Slabs

Total of 30 cm of snow since Jan 2 is mostly unconsolidated, but expect slab formation at higher elevations. Shears in this storm snow were occurring within the upper 25 cm. Any wind or warming will increase this problem dramatically.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Deep Persistent Slabs

The lower part of the snowpack is weak and will be overloaded easily with much additional load. Avoid steep (>35 degree) open slopes at treeline and above. Shallow rocky areas are likely areas to trigger this problem.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Jan 7th, 2015 4:00PM