Avalanche Forecast

Issued: Dec 28th, 2011 9:00AM

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

pgoddard, Avalanche Canada

Cariboos.

Summary

Confidence

Fair - Intensity of incoming weather is uncertain

Weather Forecast

Wednesday night: 15cm, possibly more in western areas. Moderate to strong west to south-west winds. Freezing level lowering to near valley floor.Thursday: Light snowfall. Light-moderate north-westerlies. Freezing level near valley floor.Friday: Light snow. Light south-west winds. Freezing level around 1000m. Saturday: Light flurries. Cooling temperatures. Light north-westerly winds.

Avalanche Summary

A size 2 naturally-triggered storm slab was observed on a west aspect at 2400m.

Snowpack Summary

40-80cm of total storm snow has been reported. Rising temperatures during the storm are likely to have helped form slabs within the new snow. Wind slabs exist on slopes lee to the west in the alpine and in open areas at treeline and below. A surface hoar/facet/crust interface is buried anywhere from 80-100cm deep. Avalanche activity on this layer has slowed, but it remains a concern as snow-loading gradually builds this week, particularly on slopes which did not avalanche last week. This layer is still showing easy results in some areas. A low elevation melt-freeze crust buried about half a metre deep is also one to watch. A sun crust is also buried in the alpine on some steep south and west aspects. The mid-pack is generally strong and well settled.

Problems

Storm Slabs

Up to 80cm of storm snow has fallen with warming temperatures. This is likely to have caused storm slab development.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 4

Wind Slabs

Recent storm snow is building up deeply on lee slopes as it is shifted by the wind. Be alert for wind slabs behind ridges and terrain breaks and in gullies

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

2 - 5

Persistent Slabs

A buried surface hoar layer remains a concern. It is now buried about 80-100cm deep.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 6

Valid until: Dec 29th, 2011 8:00AM