Avalanche Forecast

Issued: Jan 14th, 2014 8:24AM

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

triley, Avalanche Canada

Kootenay Boundary.

Summary

Confidence

Fair - Freezing levels are uncertain

Weather Forecast

Overnight and Wednesday: Some very light precipitation with very strong Northwest winds overnight, becoming moderate Northwest during the day. Freezing level rising to about 1800 metres during the day with some sunny periods.Thursday: Light to moderate Northwest winds with thin high cloud and a chance of sunny periods. Freezing level near 2000 metres.Friday: Warm air trapped at higher elevations. Above freezing temperatures in the alpine with sunny periods.

Avalanche Summary

Natural avalanche size 2.5 reported from the East aspect of Old Glory near Red Mountain Ski Resort, the avalanche was observed from a distance and is suspected to have failed on the November surface hoar layer. Ski cutting resulted in several dry slab avalanches releasing on Northwest aspects up to size 1.5 near Nelson. Moist snow snow-balling was reported from the Kootenay Pass area during a period of strong solar radiation. Weak base layers are suspect, especially where recent storm snow amounts are higher. Wind slab or cornice falls in motion may step down to weak layers near the ground.

Snowpack Summary

There is now about 50-80 cm above the January 8th layer of buried surface hoar and/or melt-freeze crust. Snow profile tests on the buried surface hoar layer have shown moderate sudden planar results. Deeper in the snowpack is a weak layer of surface hoar from the end of November, and in some areas depth hoar or basal facets near the ground. There is a great deal of variation across this region.

Problems

Wind Slabs

Recent storm snow has been transported into wind slabs at higher elevations. Some areas may have wind slabs that are about one metre thick.

The new snow will require several days to settle and stabilize.>Travel on ridgetops to avoid wind slabs on slopes below.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

Persistent Slabs

Recent storm snow may not be bonding to the surface hoar and melt-freeze crusts that developed before the storm. Storm slabs are more likely in areas sheltered from the recent strong winds.

Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar, facet/crust and depth hoar.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

2 - 5

Deep Persistent Slabs

Early season weak layers of surface hoar, facets, and depth hoar are now buried deep in the snowpack. This problem is more likely in areas that had a shallow snowpack during the cold arctic outbreak.

Be aware of the potential for full depth avalanches due to deeply buried weak layers.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 6

Valid until: Jan 15th, 2014 2:00PM