Archived

Avalanche Forecast

Apr 22nd, 2017–Apr 23rd, 2017

Alpine

Below Threshold

The avalanche danger rating in the alpine will be below threshold

Treeline

Below Threshold

The avalanche danger rating at treeline will be below threshold

Below Treeline

Below Threshold

The avalanche danger rating below treeline will be below threshold

Alpine

Below Threshold

The avalanche danger rating in the alpine will be below threshold

Treeline

Below Threshold

The avalanche danger rating at treeline will be below threshold

Below Treeline

Below Threshold

The avalanche danger rating below treeline will be below threshold

Alpine

Below Threshold

The avalanche danger rating in the alpine will be below threshold

Treeline

Below Threshold

The avalanche danger rating at treeline will be below threshold

Below Treeline

Below Threshold

The avalanche danger rating below treeline will be below threshold

Regions: Banff Yoho Kootenay.

With a limited freeze and new snow forecast Saturday night, the avalanche hazard will likely be elevated on Sunday. Start early and pull back from steeper objectives if the surface snow is wet or un-supportive early in the day.

Weather Forecast

Some new snow and moderate SW winds are forecasted overnight on Saturday with a limited freeze as a result of the cloud cover. Freezing levels will stay around 2000m for much of the night. A slight clearing trend Sunday afternoon and evening will allow for a better freeze on Monday morning.

Snowpack Summary

The snowpack is totally dependent on aspect and elevation now. At treeline and above, melt freeze crusts exist to ridge top on solar aspects, while on north aspects, dry surface snow still exists above ~2400m. Below treeline the snowpack becomes wet during the day and is becoming isothermal. The weak basal facets remain present in alpine areas.

Avalanche Summary

Pin wheeling on steep south aspects and some small loose wet avalanches observed on Saturday in the late afternoon.

Confidence

Avalanche Problems

Loose Wet

A limited overnight freeze on Satruday night with some new snow and afternoon warming will create loose wet problems at lower elevations and on S and W facing terrain at higher elevations. Travel early to manage this problem.

Pay attention to sluffing off cliffs and steep solar terrain, signs of a warming snowpack.

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

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

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.

Give cornices a wide berth when travelling on or below ridges.Cornices become weak with daytime heating, so travel early on exposed slopes.

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

Elevations: Alpine.

Likelihood: Possible

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 or heat. Stick to planar, supported slopes with a deeper snowpack when entering steep terrain

Pay attention to overhead hazards like cornices which could easily trigger the deep persistent slab.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 2 - 4