Avalanche Forecast

Issued: Mar 24th, 2015 8:08AM

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 and large, natural avalanches continue to occur.

Summary

Weather Forecast

Today expect a mix of sun and cloud, with alpine temps reaching -1'C and light but gusty westerly winds. On Wed a warm storm system will bring scattered flurries with freezing levels at 1700m. By Thurs freezing levels are forecast to rise to 2600m with wet flurries, alpine temps to +4'C and moderate to strong SW winds.

Snowpack Summary

50cm of snow fell in the past 5 days fell above 1800m and is settling rapidly into a slab. The upper 50cm is a complex mix of crusts, facetted snow and surface hoar which have been reactive to skier triggering. The mid Feb crust/facet/surface hoar layer is down ~75cm and is easily triggered at treeline. Cold temps overnight formed 7cm crust.

Avalanche Summary

In the park yesterday a field team found touchy conditions on northerly aspects at treeline. Convex rolls were reactive to ski cuts, triggering 65cm deep slabs. Loose snow sluffing off cliffs has been triggering similar deep slabs. Yesterday on a SE aspect, ~2200m on Mt Catamount 2 size 2.5-3 natural avalanches occurred.

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.

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

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 3

Storm Slabs

40-55cm of recent storm snow is settling into a slab and is bonding poorly where it overlies a crust. The associated winds with the storm were steady creating soft slabs in exposed areas. If triggered, the storm slab may step down to deeper layers.

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

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Mar 25th, 2015 8:00AM