Avalanche Forecast

Issued: Mar 15th, 2015 9:12AM

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

Avalanche Canada triley, Avalanche Canada

Forecast danger ratings are focused on the south of the region where heavy snowfall is expected. If you see lower snowfall amounts, these danger ratings may be a bit high.

Summary

Confidence

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

Weather Forecast

Snow above 1200 metres combined with moderate southwest winds tonight and Monday morning. 15-30 cm of snow is forecast for alpine elevations by late Monday morning. Monday should be cloudy with some lingering flurries and light easterly winds. Freezing levels should drop down to about 1000 metres by Tuesday morning. Mostly sunny with light winds on Tuesday and freezing levels rising up to about 1800 metres. Cloudy on Wednesday with moderate southwest winds and light precipitation.

Avalanche Summary

No new avalanches reported. I expect new snow and wind to create fresh windslabs that may be very touchy to human triggers.

Snowpack Summary

Forecast heavy precipitation is expected to fall as snow above about 1200 metres. New snow and wind are expected to develop new storm slabs above the rain soaked snowpack. Heavy rain on Saturday soaked the snowpack up to ridge tops. Strong southwest winds combined with new snow at higher alpine elevations may have developed new wind slabs that are easy to trigger, and may allow for long propagations where they are sitting on a crust/facet combination. The most prominent feature in the snowpack is the thick late-February crust, down 5-20 cm before the ongoing storm. Limited reports suggest this crust is breaking down in some areas, while it remains supportive all the way to ridge crest in other spots. Deeply buried persistent weak layers still exist in the snowpack. These layers have not been reactive lately, however the extremes of warm weather followed by heavy loading due to rain then followed by snow, make it difficult to assess how the snowpack will respond.

Problems

Storm Slabs

An icon showing Storm Slabs
Forecast heavy snow and wind are expected to develop new storm slabs in the alpine and at treeline.
The new snow will require several days to settle and stabilize.>Avoid avalanche terrain during periods of heavy loading from new snow and wind.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 4

Valid until: Mar 16th, 2015 2:00PM