Avalanche Forecast

Issued: Jan 18th, 2012 9:26AM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is moderate. Known problems include Wind Slabs and Loose Dry.

Avalanche Canada jfloyer, Avalanche Canada

Summary

Confidence

Fair - Intensity of incoming weather is uncertain

Weather Forecast

Thursday: should stay cold and dry, although not quite as cold as it has been (-11C at treeline expected). Winds will increase slightly but should stay in the moderate range, and will shift back around to the west. Friday: a storm is approaching, which will hit the region late in the day. Anticipated amounts are 5-10 cm new snow with temperatures rising to around -6C. On Saturday, a further 10-15 cm new snow is anticipated, with freezing levels possibly rising briefly to 1500 m.

Avalanche Summary

Ski cutting produced size 1 loose and occasional soft slab avalanches on Wednesday with minimal propagation. Widespread sluffing to size 1 was noted on Tuesday and Wednesday in the new snow on steep terrain.

Snowpack Summary

The storm on Monday night/Tuesday added 15 to 40 cm very low density new snow, bring average treeline snow depths to around 200 cm. Cold temperatures have kept the snow light and cohesionless in most areas, despite recent moderate winds that have been blowing snow around a little. A crust now lies buried around 25-45 cm below the snow surface at elevations below 1900 m. Some areas reported this crust had a layer of surface hoar on it when it was buried. It appears at this time as though the snow has not yet settled enough to produce much slab avalanche activity on this layer yet. However, when the upper slab does become sufficiently cohesive, more dangerous avalanche conditions will start to set up. There is a blog posting on the Forecaster Blog (link on the sidebar on the left) that discusses this issue in more depth. The mid-December surface hoar/facet persistent weakness, now down 70-120 cm, remains a concern with heavy triggers in thin slab areas.

Problems

Wind Slabs

An icon showing Wind Slabs
Shifting winds have set up soft wind slabs in a variety of areas on lee slopes in exposed areas.

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

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Loose Dry

An icon showing Loose Dry
Low density new snow is shedding easily on steep terrain, resulting in widespread sluffing.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Very Likely

Expected Size

1 - 3

Valid until: Jan 19th, 2012 8:00AM