Avalanche Forecast

Issued: Mar 26th, 2015 4:38PM

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

brian webster, Parks Canada

Banff Yoho Kootenay.

Pay attention to the freezing levels. Some forecasts have freezing levels going up to 2600 m on Friday.

Summary

Weather Forecast

Freezing Levels forecasted to rise to 2500m on Friday with a cooling trend starting on Saturday. Friday will be mainly cloudy with some scattered flurries moving in on the weekend.

Snowpack Summary

20-30 cm of recent storm snow at upper elevations is starting to form soft wind slabs on lee terrain in the alpine. These wind slabs overlay a variety of hard surfaces particulary on south aspects. Moist surface snow on south aspects up to ridge line. In most places the base of the snowpack is made up of weak facets and depth hoar.

Avalanche Summary

One skier triggered size 1.5 wind slab reported from a SE aspect at 2700 m in Bow Summit area.

Confidence

Freezing levels are uncertain on Friday

Problems

Wind Slabs

There is generally 10-20 cm available for transport and moderate to strong SW wind continues to build windslabs. They are sensitive to human triggering on features such as ridge crests, cross loaded gullies, and steep lee terrain features.

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

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Loose Wet

Rising freezing levels on Friday has the potential to create a loose wet avalanche problem on solar aspects

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Deep Persistent Slabs

The lower half of the snowpack is weak due to the presence of basal facets and depth hoar. This layer has been dormant lately but may become more sensitive with the rising temperatures.

Be aware of thin areas that may propogate to deeper instabilites.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely

Expected Size

2 - 3

Valid until: Mar 27th, 2015 4:00PM