Avalanche Forecast

Issued: Jan 5th, 2014 8:45AM

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

triley, Avalanche Canada

South Coast.

Warm air in the alpine combined with strong solar radiation may result in elevated danger on South aspects where buried surface hoar and crusts are a concern.

Summary

Confidence

Fair - Timing of incoming weather systems is uncertain on Wednesday

Weather Forecast

Monday: Winds becoming moderate Southwest overnight. High cloud with sunny periods in the morning becoming mostly cloudy in the afternoon. A layer of warm air that may be above freezing is expected to sit at alpine elevations until early Tuesday morning.Tuesday: Moderate Southwest winds and light precipitation with freezing levels dropping down to about 1000 metres near the coast and 500 metres inland.Wednesday: The next Pacific system is expected to move onto the coast. Models disagree on the timing and intensity of this next system.

Avalanche Summary

Two size 2.0 natural slab avalanches that were about 50 cm deep released on South aspects above the highway in the Duffey Lake area. These avalanches released during warm temperatures and direct solar exposure. Continued forecast warm air at higher elevations may continue to weaken the bond between buried surface hoar and a crust.

Snowpack Summary

Snowpack depths at treeline range from 130-170 cm in the South of the region, and from 80- 130 cm in the North of the region. The recent storm snow has settled down to about 15 cm in the Coquihalla and is reported to be bonding well to the old surface, however easy shears may be found in the storm snow where it was transported into a soft wind slab. In the Duffey lake area the recent storm snow is reported to be bonding to a thin crust. Below this crust weak layers of buried surface hoar are resulting in moderate sudden collapse type shears down 25-35 cm. The snowpack in the Duffey lake area has been described as "unusually facetted and low density."

Problems

Wind Slabs

Recent storm snow and strong winds have created pockets of wind slab in the alpine and at treeline. Wind slabs may be sitting above weak shallow snowpacks.

Be careful with wind loaded pockets near ridge crests and in terrain depressions>Use ridges or ribs to avoid pockets of wind loaded snow.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Persistent Slabs

Weak layers of buried surface hoar, crusts, and depth hoar may continue to be triggered by light additional loads like skiers and riders. Moist loose snow falling from steep solar aspects may trigger buried weak layers.

Use caution in shallow snowpack areas where triggering is more likely.>Use caution on open slopes and convex rolls at treeline where buried surface hoar may be preserved.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 4

Valid until: Jan 6th, 2014 2:00PM