Avalanche Forecast

Issued: Jan 3rd, 2014 8:11AM

The alpine rating is considerable, 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.

Summary

Confidence

Fair - Due to the number of field observations

Weather Forecast

Overnight and Saturday: Mostly clear overnight with a mix of sun and cloud during the day. Cooler more seasonal temperatures with alpine lows about -10. Light to moderate Northwest winds and no precipitation.Sunday: Mix of sun and cloud with an area of warm air moving into alpine elevations pushed by moderate Southwest winds. Above freezing temperatures are expected in the Alpine.Monday: Continued warm air at higher elevations with light to moderate Southwest winds and no precipitation.

Avalanche Summary

No new natural avalanches reported during the storm due to poor visibility and travel conditions. One skier controlled size 2.0 avalanche that ran on mid december buried surface hoar in the Duffey Lake area.

Snowpack Summary

New snow is expected to be poorly bonded, especially on wind-loaded slopes. Snowpack depths vary greatly across the region with 180cm at treeline in the Cascades but only about 80cm in the Duffey Lake area, and terrain below treeline is still mostly below threshold for avalanche activity. In general the snowpack is shallow with a faceted and weak lower half, but also highly variable. Snowpack testing on a NW facing slope at 2150m in the Duffey Lake area on Thursday produced easy sudden planar compression test results, and a RB2, whole block release Rutschblock result down 27cm on the late-December surface hoar, this layer now has an additional 15-25 cms since the Thursday evening storm. Early season riding hazards such as rocks, stumps and logs are lurking below the surface at treeline elevations and below.

Problems

Wind Slabs

New storm snow amounts vary from 30-40 in the Cascades to 10-20 in the Duffey Lake area. Wind slabs that developed during the storm are expected to become more stubborn to trigger.

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, South.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Persistent Slabs

There is now close to 50 cm above this weak layer in the Duffey Lake area. Snowpack tests show that this layer may be triggered by light additional loads.

Dig down to find and test weak layers before committing to a line.>Use caution in shallow snowpack areas where triggering is more likely.>Watch for whumpfing, hollow sounds, shooting cracks or recent avalanches.>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

1 - 5

Valid until: Jan 4th, 2014 2:00PM