Avalanche Forecast

Issued: Feb 3rd, 2013 8:31AM

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

triley, Avalanche Canada

South Columbia.

Summary

Confidence

Fair - Forecast snowfall amounts are uncertain on Tuesday

Weather Forecast

Overnight and Monday: Strong Westerly winds with 5-10 cms of snow and alpine temperatures down to -8.0. A few cms during the day with gusty Northwest winds and freezing levels rising to about 900 metres.Tuesday: A warm pulse of moisture is expected to bring 10-15 cms to elevations above 1000 metres with strong Southwest winds.Wednesday: Strong Westerly winds and flurries. Freezing level up to 1100 metres during the day.

Avalanche Summary

The sun caused a natural cycle of loose and slab avalanches up size 2.0 that were mostly started in very steep un-skiable terrain. Wind slabs also continued to release naturally or were triggered by skiers. The West Monashee continued to be the most reactive area reported, with natural avalanches up to size 3.5 that were releasing in the recent storm snow.

Snowpack Summary

Wind slabs continue to develop in the alpine and at treeline. A sun crust has developed on steep Southerly aspects, and a melt-freeze crust has developed at lower elevations due to the recent high freezing levels. The recent storm slab continues to be reactive at treeline and below on steep convex slopes that have buried surface hoar at the January 23rd interface (between 40-60 cms down). The mid-pack is well settled and strong. There are a few locations that continue to find a well preserved surface hoar layer from early January that is buried down about 90 cms. Forecast cooler temperatures should help to strengthen the recent storm slab where it became moist at lower elevations.

Problems

Wind Slabs

Old wind slabs are expected to continue to be triggered by light additional loads. New wind slabs are expected to build during the next pulse of moisture.

Be cautious as you transition into wind affected terrain.>Use ridges or ribs to avoid pockets of wind loaded snow.>

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 4

Persistent Slabs

The recent storm slab continues to be reactive above variable sliding surfaces.

Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.>Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 5

Valid until: Feb 4th, 2013 2:00PM