Avalanche Forecast

Issued: Apr 13th, 2018 4:00PM

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

conrad janzen, Parks Canada

Banff Yoho Kootenay.

The alpine hazard will slowly increase as new snow arrives. Watch for wind loading, and the bond with buried sun crusts. Lower elevation hazard will fluctuate with the temperatures, rising during the day and lowering overnight.

Summary

Weather Forecast

Saturdays forecast is for 5-10 cm of snow along the divide with snow fall amounts easing off by mid day, and moderate SW winds in the alpine. Freezing levels are forecast to stay below 2000m. An additional 5-10 cm is forecast for Sunday night along the divide, though not much is expected in the Eastern parts near the town of Banff.

Snowpack Summary

5-8 cm of new snow on Friday with wind effect in the alpine from Mod SW winds and thin wind slabs in lee areas. The March 15 sun crust is down 25-50 cm on solar aspects in the alpine and still a concern in some locations. Various temperature crusts and/or moist snow can be found on solar aspects in the alpine and on all aspects below 2000m.

Avalanche Summary

Some thin touchy skier controlled wind slabs were reported on Friday from the local ski hills up to size 1, with propagations of up to 50 m wide on solar aspects. No new natural avalanches were observed on a flight to the Wapta Icefields Friday morning.

Confidence

Forecast snowfall amounts are uncertain on Saturday

Problems

Wind Slabs

With some new snow and stronger SW winds the wind slabs have become a bit more reactive over the past 24 hrs, especially where present over a buried sun crust.

Be careful with wind loaded pockets, especially near ridge crests and roll-overs.Watch for shooting cracks or stiffer feeling snow. Avoid areas that appear wind loaded.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Persistent Slabs

Forecasters are still concerned about the Mar 15 sun crust which is down 25-50 cm on steeper solar aspects. There have been sporadic skier and explosive triggered avalanches on this layer over the past several weeks, but nothing in the last few days.

Be cautious with convexities and steep slopes on solar aspects.

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

Elevations: Alpine.

Likelihood

Unlikely

Expected Size

1 - 2.5

Valid until: Apr 14th, 2018 4:00PM