Avalanche Forecast

Issued: Jan 4th, 2013 9:05AM

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

triley, Avalanche Canada

Northwest Inland.

Summary

Confidence

Fair - Timing, track, or intensity of incoming weather is uncertain on Saturday

Weather Forecast

Overnight and Saturday: Dry and cool overnight with no precipitation. Light precipitation starting in the morning, expect 5-10 cms during the day. Winds becoming strong Southerly on Saturday. Freezing level rising up to about 1000 metres.Sunday: Light precipitation is expected to continue during the day. Winds becoming moderate Westerly. Alpine temperatures around -5.0 and freezing levels at about 700 metres.Monday: Continued light precipitation. Temperatures cooling off to about -10.0 in the alpine overnight.

Avalanche Summary

No new reports of avalanche activity. Wind slabs in the Howson Range ( Southwest of the region where it tends to get more snow) were quick to settle out after the last storm, becoming very stubborn by the day after the storm.

Snowpack Summary

The snowpack is generally shallow (about 1m deep) and strong winds have scoured some alpine slopes to ground. Wind slabs exist in many wind-exposed areas. Their distribution is quite variable and some areas have no wind-effect at all. It is still possible to find cold, low density snow at the surface in wind sheltered areas. Below treeline, very loose cold snow is sluffing easily from steep terrain and early season hazards like exposed stumps and rocks are still present in places. Professionals are still mindful of a facet/crust layer near the base of the snowpack. Although triggering it has become unlikely, it may be possible from a thin-spot trigger point or with a very heavy load (e.g. cornice fall). A size 2 natural slab avalanche triggered by a cornice fall that occurred on December 28th in the Hankin area illustrates that caution is still warranted for this layer.

Problems

Wind Slabs

Wind slabs may be triggered by the additional load of a skier or rider.

Avoid freshly wind loaded features.>Be cautious as you transition into wind affected terrain.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

Deep Persistent Slabs

A deeply buried facet/crust weakness exists near the base of the snowpack. This layer could be triggered by large loads such as a cornice collapse or from a thin-spot trigger point.

Avoid convexities or areas with a thin or variable snowpack.>Avoid thin, rocky or sparsely-treed slopes.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 5

Valid until: Jan 5th, 2013 2:00PM