Avalanche Forecast

Issued: Dec 20th, 2013 8:54AM

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

ghelgeson, Avalanche Canada

Cariboos.

Summary

Confidence

Fair - Due to the number of field observations

Weather Forecast

Synopsis: The pattern remains firmly NW and as a result the coast mountains get the bulk of the action but there should still be a little precip left over for Cariboo for the period. Freezing levels should climb to 1200m by Monday.Saturday: Freezing Level: Valley Bottom; Precip: Nil Wind: Lht NWSunday: Freezing Level: Valley Bottom Precip: 2/4mm 4/8cm Wind: Light gusting strong S Snow picking up in intensity Sunday evening into Monday.Sunday evening: Precip: 8/10mm 16/20cmMonday: Freezing Level: 1200m Precip: Nil Wind: Mod gusting Strong, W

Avalanche Summary

A few natural size 2 avalanches were observed Friday on a north facing slope with a shallow snowpack.

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 may still be sensitive to human triggering. Watch for these wind slabs in open terrain at and above treeline.

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

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

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

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

3 - 5

Valid until: Dec 21st, 2013 2:00PM