Avalanche Forecast

Issued: Mar 3rd, 2014 4:00PM

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

conrad janzen, Parks Canada

Banff Yoho Kootenay.

New snow, wind and warmer temperatures are slowly increasing the avalanche hazard. We also have a fair bit of uncertainty about how well the Feb 10th layer is bonding. Treat all steeper terrain with caution.

Summary

Weather Forecast

An additional 5-10cm of snow is forecast each day through Thursday accompanied by moderate SW winds. Alpine temperatures in the -15'C to -5'C range with warming temperatures forecast for Thursday.

Snowpack Summary

10cm of new snow today with moderate SW winds. 30-45cm of snow sits on the Feb10th layer comprised of facets, surface hoar, and on solar aspects a sun crust. Test results are generally in the moderate to hard range but still show that propagations are possible in many areas. Some whumphs on this layer today. No shears found in the basal layers.

Avalanche Summary

One size 1.5 skier accidental was reported yesterday on an E aspect at 2350m near Bow Summit which failed on the Feb 10th layer. Some natural loose snow avalanches up to size 1, and a small wind slab triggered with explosives were also reported today.Â We expect to see a gradual increase in avalanche activity over the next few days.

Confidence

Intensity of incoming weather systems is uncertain

Problems

Persistent Slabs

This layer is slowly gaining strength however test results continue to show that wide propagations are possible in some areas which would lead to severe consequences. Sudden collapse results and low scores in propagation saw tests are still common.

Assess start zones carefully and use safe travel techniques.Dig down to find and test weak layers before committing to a line.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 2

Wind Slabs

The new snow and moderate SW winds are staring to build soft slabs in lee areas above tree line. Probe for these with your poles and avoid steep wind loaded slopes. Sluffing out of steep terrain is also expected as more new snow arrives.

Be cautious as you transition into wind affected terrain.Use caution in lee areas. Wind slabs may step down to deeper layers resulting in large avalanches.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Mar 4th, 2014 4:00PM