Avalanche Forecast

Issued: Feb 19th, 2016 8:30AM

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

Avalanche Canada triley, Avalanche Canada

Snowfall amounts overnight are uncertain and may be higher in western upslope areas. We are also unsure of when and where the sun will shine. Solar radiation on dry storm snow is a concern for increased avalanche activity.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain

Weather Forecast

Moderate southwest winds and 3-5 cm of new snow overnight. Winds becoming strong from the west during the day on Saturday as a weak ridge of high pressure builds after the storm. There may be some sunny breaks Saturday afternoon, but more likely to clear overnight. Freezing levels bouncing between valley bottoms and 1400 metres. Mostly sunny on Sunday with light winds and freezing levels up to 1200 metres. Cloudy with increasing southwest winds on Monday.

Avalanche Summary

Wind loading followed by solar radiation resulted in a size 3.0 natural storm slab avalanche on a south aspect in the alpine on Friday. Another natural cornice fall size 2.0 was reported on Thursday from a north aspect in the alpine, it was also reported that this cornice did not release a storm slab on the slope below. On Wednesday a natural cornice fall resulted in a size 2.0 avalanche.

Snowpack Summary

Another 5-15 cm of new snow was reported on Friday morning. Each pulse of snow and wind continues to add to the wind slabs and settling storm snow from the past few days. About 40-60 cm below the surface, you'll likely find a melt freeze crust. This crust exists in most places except for higher elevation shaded terrain. In many areas there seems to be a reasonable bond between the crust and the overlying snow. I'd still keep an eye on this interface as it has become reactive on some features. Surface hoar buried in early January now lies up to 180cm below the surface and has become less of a concern. Possible triggers for this deep and destructive layer include a large cornice fall or significant warming.

Problems

Storm Slabs

An icon showing Storm Slabs
Storm slabs may continue to develop with forecast new snow and wind. Dig down and test the bond between the recent storm snow and the buried crust below.
Use ridges or ribs to avoid wind loaded terrain.>Minimize exposure during periods of heavy loading from new snow, wind.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 4

Cornices

An icon showing Cornices
Cornices may be large and fragile. Cornice growth continues with each pulse of new snow and wind. Natural cornice falls may trigger storm slab avalanches on the slopes below.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 4

Valid until: Feb 20th, 2016 2:00PM