Avalanche Forecast

Issued: Apr 18th, 2017 4:00PM

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

grant statham, Parks Canada

Banff Yoho Kootenay.

Conditions are highly variable right now, and the danger ratings represent the highest danger rating for the day. Avalanche danger is lower in the morning when the snow surface is frozen, and before the air temperatures warm up. Start early.

Summary

Weather Forecast

Clearing through the day on Wednesday, with sun patches appearing in the afternoon. Expect a high of 0 degrees at treeline, and lows of -10 early in the morning. Trace amounts of snow expected overnight for Wednesday.

Snowpack Summary

The snowpack is a real mixed bag right now: totally dependent on aspect and elevation. At treeline and above, 5-10 cm of new snow overlies a strong melt-freeze crusts to ridge top on solar aspects, and 2000m on north aspects. Below treeline the snowpack becomes wet through the day. The snowpack has not converted to spring conditions yet.

Avalanche Summary

No new avalanches reported or observed today.

Confidence

Problems

Loose Wet

Afternoon warming will create loose wet problems at low elevations and on S and W facing terrain at higher elevations.

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Cornices

Cornices continue to fail. Minimize your time underneath these and remember that a cornice failure could also trigger the deep persistent slab on the basal facets.

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

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

1 - 3

Deep Persistent Slabs

The snowpack is gaining strength, but the weak basal facets continue to produce sudden collapse results and can produce large avalanches with large triggers. Stick to planar, supported slopes with a deeper snowpack if entering steep terrain.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 4

Valid until: Apr 19th, 2017 4:00PM