Avalanche Forecast

Issued: Mar 25th, 2015 8:00AM

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

danyelle magnan, Parks Canada

Glacier.

The upper snowpack is touchy and complex. Layers in the top meter are sensitive to human triggering. Avalanche danger is expected to rise as another warm, wet and windy storm moves into the region late today.

Summary

Weather Forecast

Flurries have started as a warm storm approaches. By thurs morning we will see 5-10cm with freezing levels to 1800m and gusty SW winds. On Thursday freezing levels will rise to 2800m with rain/flurries. Alpine temps are forecast to reach +4'C with moderate SW winds. Friday will be similar; the low is +1'C with continued showers and winds to 75km/h.

Snowpack Summary

50cm of storm snow above 1800m and is settling into a slab. Below the storm slab is a complex mix of crusts, facetted snow and surface hoar which have been reactive to skier triggering. A facetted layer sitting on a crust down ~65cm and is easily triggered at treeline. Tests on this layer indicate that if triggered avalanches can propagate widely.

Avalanche Summary

Conditions are touchy at treeline. Convex rolls are reactive to ski cuts, triggering 65cm deep slabs. Loose snow sluffing off cliffs has been triggering similar slabs. Yesterday strong solar in the afternoon triggered a size 2 in "Frequent Flyer" up Connaught, which ran into the avalanche fan stopping above the uptrack.

Confidence

Timing, track, or intensity of incoming weather system is uncertain

Problems

Persistent Slabs

Persistent weak layers down 50-100cm have been triggered recently by light loads, such as skiers or sluffing off of cliffs. These layers have been remotely triggered, and have the tendency to propagate widely.

Be aware of the potential for large, deep avalanches.Choose well supported terrain without convexities.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 3

Storm Slabs

Recent storm snow is settling into a slab and is bonding poorly where it overlies a crust. SW winds are increasing and are creating pockets of windslab at ridgetop. As freezing levels rise the slab may become more reactive.

The new snow will require several days to settle and stabilize.Be cautious as you transition into wind affected terrain.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Mar 26th, 2015 8:00AM