Avalanche Forecast

Issued: Jan 20th, 2012 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 Storm Slabs.

Avalanche Canada triley, Avalanche Canada

Summary

Confidence

Fair - Forecast snowfall amounts are uncertain on Saturday

Weather Forecast

Overnight snowfall is expected to accumulate up to about 15-20 cm by Saturday morning. The new snow should be combined with light to moderate southerly winds and alpine temperatures around -14.0. The wind is expected to increase during the day on Saturday and become gusty up to about 60km/hr from the southwest. Another 5-10 cm is expected during the day on Saturday. Sunday is forecast to be unsettled with flurries and possibly some sunny breaks. Flurries are expected again on Monday, possibly increasing to moderate snowfall in the afternoon. The freezing level is forecast to remain at valley bottoms during this forecast period.

Avalanche Summary

No new reports of avalanches observed.

Snowpack Summary

New snow beginning to develop, about 3-5 cm by noon on Friday. The snowpack depth in the Smithers-Hankin area is about 250-275 cm at the upper extent of the treeline elevation band. Some surface facetting has been observed above treeline, and some surface hoar observed below treeline. Very strong northeast outflow winds have scoured north and east aspects and reduced previous cornice growth. The snow has been transported into stiff windslabs on south through west aspects. These windslabs should be stiff enough in most areas that the forecast southerly winds will not be able to re-distribute the snow. The mid-december crust has been observed to have bonded to the mid-pack in most areas, but may be found to have become facetted in areas with a shallow snowpack. The mid-pack is considered to be strong and well settled in most areas. No basal weak layers of concern have been reported.

Problems

Wind Slabs

An icon showing Wind Slabs
Stiff windslabs have developed during the strong northeast outflow winds. New soft windslabs are expected to develop as the new storm develops from the south or southwest.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

2 - 5

Storm Slabs

An icon showing Storm Slabs
Dry light snow falling at the beginning of the storm may become heavier as the temperatures rise, and develop a storm slab that may not bond to the old cold surface. If temperatures stay cool, expect sluffing in the new snow.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 4

Valid until: Jan 21st, 2012 8:00AM