Avalanche Forecast

Issued: Mar 16th, 2015 8:06AM

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

Lydia Marmont, Parks Canada

Glacier.

Watch for and avoid wind loaded areas on all aspects. Expect these areas to be easy to trigger especially when the sun comes out.

Summary

Weather Forecast

Sunshine is expected for the next two days with light variable winds at mountain top and freezing levels rising from valley bottom to 1900m. On Tuesday evening another weak front will pass through bring small amounts of precipitation on Wednesday. A strong front is expected to arrive by the weekend with the potential for a lot of moisture.

Snowpack Summary

At treeline and above, pockets of winds slab up to 30cm thick formed by strong to extreme winds on Saturday night overlie a combination of crusts, settling snow and the Feb19th surface hoar down 45cm. Yesterday the new wind slab was failing with skier traffic. Below 1800m the surface is a crust formed by 10mm of rain on Saturday.

Avalanche Summary

Yesterday skiers reported triggering a Sz 2.5 avalanche in the Ursus area 25cm deep, 150-200m wide. Lots of whumphing was observed at TL. Natural moist/wet and slab avalanches to Sz 3.0 occured on Saturday. Two days ago on Dome Glacier, a size 2.0 wind slab was triggered by the 5th skier on the slope, running 130m to the bench below the headwall.

Confidence

Problems

Wind Slabs

Sustained strong to extreme SW winds Saturday night and Moderate N winds last night creating widespread wind slabs which are reactive to human triggering. Expect these slabs to become even more reactive with solar radiation.

Avoid freshly wind loaded features.Watch for whumpfing, hollow sounds, and shooting cracks.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Storm Slabs

~20cm of dense storm snow at tree line and above. The first significant snowfall in quite some time overlies a variety of surfaces from crust, to facets to wind slab.

If triggered the storm slabs may step down to deeper layers resulting in large avalanches.Avoid cross loaded features.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Persistent Slabs

A multitude of crusts are buried within the top meter of the snowpack. These have may become reactive with the new load we received and with solar radiation. The bridging properties of near surface crusts weaken as the snowpack warms.

Be aware of the potential for large, deep avalanches.Be aware of the potential for wide propagations.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 3

Valid until: Mar 17th, 2015 8:00AM