Avalanche Forecast

Issued: Jan 26th, 2016 4:00PM

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

Ian Jackson, Parks Canada

Banff Yoho Kootenay.

Storms are on the horizon! Heads up for changing conditions and adapt your mindset to reflect the elevated danger ratings!

Summary

Weather Forecast

A couple of systems are on track to bring some precipitation in the next few days. It has already started snowing as of this afternoon and we can expect 5-10 cm overnight on Tuesday with moderate to strong SW winds. A short break on Wednesday PM and then another 5 - 15 cm overnight Wednesday and into Thursday. 1500 to 1700 m freezing levels.

Snowpack Summary

20-50 cm of new snow overlies the January 6th surface hoar/ facet layer. This layer is most prominent and reactive in the Kootenay region. In the alpine, this snow has been blown into fresh windslabs by moderate SW winds. The middle of the snowpack is facetted which has allowed recent avalanches to gain mass. A rain crust exists below 1500 m.

Avalanche Summary

Monday's avalanche control work in Kootenay resulted in widespread avalanches between size 2 and 3 with fracture lines ranging from 25-50 cm deep failing on the Jan 6th layer of surface hoar and facets. On Tuesday, local ski hills reported several size 1.5 -2 windslabs triggered with explosives in steep alpine terrain.

Confidence

Timing, track, or intensity of incoming weather system is uncertain

Problems

Wind Slabs

With the incoming wind and precipitation, we can expect touchy conditions on lee features at treeline and above. These windslabs have triggered persistent slabs and entrained facets at lower elevations recently resulting in large avalanches recently

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

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Persistent Slabs

The new snow is settling into a 15- 40 cm slab above the Jan. 6th surface hoar and facet layer. This layer is most reactive where there is a thicker slab and buried surface hoar (between 1500 and 2000m in Kootenay).

Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 3

Valid until: Jan 27th, 2016 4:00PM