Avalanche Forecast

Issued: Mar 22nd, 2015 4:00PM

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

aaron beardmore, Parks Canada

Banff Yoho Kootenay.

Limit your exposure late in the day and during warm periods. An isothermal snowpack at low elevations should be expected.

Summary

Weather Forecast

A mix of sun and cloud for the next couple of days intermixed with the odd convective cell which brings a few centimeters of snow. The solar energy from the clear periods will have a strong impact on the snow surface late in the day.

Snowpack Summary

10 - 15cm of snow over the last 72 hours in the alpine with moderate SW winds and temps near 0`C. Wind slabs present in isolated lee and open areas in the alpine. The recent snow sits on a variety of stiffer surfaces. The base of the snowpack is made up of facets and depth hoar and remains weak. Below tree line snow is isothermal in the afternoons.

Avalanche Summary

Sunshine Backcountry: 1. Peak 2880 North of Fatigue Mtn: Size 2 windslab 50m wide 50cm deep and 400m long in steep terrain in the immediate lee within the last 48 hours 2. Newfie Bowl (adjacent to Bye Bye Bowl): Size 2 windslab 80m wide 40cm deep and 200m long at 2400m in elevation. Steep rocky terrain in immediate lee within the last 24 hours.

Confidence

Problems

Wind Slabs

10 cm of recent storm snow has formed wind slabs up to 35cm in the lee areas at treeline and above. These will be sensitive to human triggering on features such as ridge crests and cross loaded gullies. Please see avalanche activity for recent obs.

Use caution in lee areas. Recent wind loading have created wind slabs.Be cautious as you transition into wind affected terrain.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Loose Wet

Recent rain has helped produce isothermal conditions below treeline, especially in the afternoon as a result of daytime warming.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

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 forecasted new snow load, especially in thin areas.

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

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Mar 23rd, 2015 4:00PM