Avalanche Forecast

Issued: Jan 27th, 2013 9:48AM

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

jfloyer, Avalanche Canada

South Columbia.

Summary

Confidence

Fair - Freezing levels are uncertain on Tuesday

Weather Forecast

Synopsis: Northwesterly flow will bring a series of low-intensity pulses of precipitation interspersed with short-lived periods of clear weather to the region through the forecast period. Temperatures will start out fairly cool but rise through Tuesday and into Wednesday to become mild.Monday: Flurries. Treeline temperatures around -7C. Light westerly winds.Monday night: Light snowfall, around 5cm.Tuesday: Mainly dry during the day. Temperatures rising to a high of -2C at treeline elevations. Northwesterly winds, gusting to 30km/h at ridgetop.Wednesday: Light snowfall, up to 5cm. Treeline temperatures around 0C. Northwesterly winds gusting to 50km/h at ridgetop.

Avalanche Summary

On Thursday and Friday, a relatively small natural avalanche cycle took place in the storm snow up to size 2 which ran on the January 23rd interface, mostly on N and E facing slopes. Over the weekend, only a couple of small slab avalanches on northerly aspects were reported.

Snowpack Summary

Approximately 30 to 50 cm of recent storm snow overlies a weak layer comprising of surface hoar in shady locations, facets at higher elevations and a sun crust on solar aspects. The recent new snow sitting above this interface has been slowly consolidating from fresh powder into a more cohesive slab. A mid-pack surface hoar layer buried in early January is down around 90 cm, and is best preserved below approximately 1700 m. A freezing rain crust has been reported near the surface (it may now be buried by light snow) in the Monashees, particularly in areas close to Mabel Lake.

Problems

Storm Slabs

Watch for storm snow settling into a more cohesive slab on steep southerly slopes where it covers a crust or shady sheltered slopes in open glades where it rests on surface hoar. Pillows of windslab are likely on N or E facing slopes behind ridges.

Whumpfing, shooting cracks and recent avalanches are all strong indicators of an unstable snowpack.>Watch open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.>Use ridges or ribs to avoid pockets of wind loaded snow.>Assess start zones carefully and use safe travel techniques.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 4

Valid until: Jan 28th, 2013 2:00PM