Avalanche Forecast

Issued: Dec 19th, 2013 9:13AM

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

ghelgeson, Avalanche Canada

Cariboos.

Forecasters are operating with limited field data at this time. If you've been in the backcountry we'd love to hear what you're seeing. Please send observations to: forecaster@avalanche.ca

Summary

Confidence

Fair

Weather Forecast

Synopsis: Upper NW flow brings significant precipitation to the North Coast over the next few days. A small amount of snow will make it to the Cariboos accompanied by variable winds.Friday: Freezing Level: Valley Bottom; Precip: 2/4mm 4/8cm Wind: Light NWSaturday: Freezing Level: Valley Bottom; Precip: Trace Wind: Lht gusting Strong, NWSunday: Freezing Level: 800m Precip: Trace; Wind: Light SW

Avalanche Summary

A small wind slab avalanche cycle to size 2 was reported Wednesday.

Snowpack Summary

Snowpack depths vary widely with reports of up to 180cm at tree line in some parts of the region. The upper snowpack contains storm snow, wind slabs, surface hoar, and facets. Previously warm temps and as much as 70cm of new snow have combined to form a cohesive slab on top of the surface hoar and facets. It's difficult to determine if the slab is currently reactive to light triggers like skiers and sledders. Deeper in the mid-pack a couple of persistent weak layers (surface hoar and facets) can be found that formed in mid and late November. Near the base of the snowpack an early season rain crust exists.

Problems

Wind Slabs

Moderate winds continue to redistribute storm snow and create fresh wind slabs. These wind slabs likely remain sensitive to human triggering. Watch for these wind slabs in open terrain at and above treeline.

Avoid freshly wind loaded features.>Stay off recent wind loaded areas until the slope has had a chance to stabilize.>Use ridges or ribs to avoid pockets of wind loaded snow.>

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 4

Persistent Slabs

A buried persistent weak layer of facets, surface hoar, and/or a crust is buried by 40-70 cm of storm snow and may be susceptible to human triggering. Wind slab avalanches may step down and trigger larger persistent slab avalanches.

Be especially cautious near rock outcroppings, on steep convexities and anywhere the snowpack feels thinner than average.>Choose conservative well supported lines and watch for clues of instability.>Be aware of the potential for large, deep avalanches due to the presence of buried weak layers.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

3 - 5

Valid until: Dec 20th, 2013 2:00PM