Avalanche Forecast

Issued: Nov 10th, 2015 4:00PM

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

grant statham, Parks Canada

Banff Yoho Kootenay.

Lots of keen climbers and skiers out there, but the snowpack is weak and skiing is marginal in all but high, glaciated terrain. People are triggering avalanches, and it looks like the first avalanche cycle of the winter on Friday and Saturday!

Summary

Weather Forecast

Looks like a stormy week ahead, as a NW flow brings 10 cm of snow by mid-day on Wednesday while temperatures remain cool (-8 to -11). After a short break on Thursday, looks like a pumper of a storm for Friday with amounts up to 30 cm being predicted . . . alas, accompanied by significant warming. Expect an avalanche cycle on Friday up high.

Snowpack Summary

Total snowpack depths range from 35-45 cm at treeline across the forecast area with a 5mm layer of surface hoar on the surface. Approximately 25 cm of light snow overlies slightly stronger layer that sits on the ground. Two shears exist: one on the ground, and another down 15 cm from the top. Overall this snowpack is weak with little structure.

Avalanche Summary

Slabs and loose snow avalanches have been triggered and are running naturally from alpine features, up to about size 2.5. In confined areas, the debris has run down to treeline areas. Today at Bow Summit a size 1.5 avalanche was remotely triggered on the ground, 35m ride and ran 80 m. On the Wapta, a group remotely triggered a size 2 on Mt. Olive.

Confidence

Problems

Wind Slabs

Avalanches up to 50 cm deep are being triggered in many areas in high alpine, glaciated terrain. Watch out for windloaded features which should be avoided at this time as triggering is easy.

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

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

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

1 - 3

Loose Dry

The entire snowpack is unconsolidated, and loose avalanches have been observed to have run through confined gully areas - this is something ice climbers should keep in mind as they consider any overhead hazards to their routes.

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Nov 11th, 2015 4:00PM