Avalanche Forecast

Issued: Feb 3rd, 2013 8:28AM

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

Purcells.

Summary

Confidence

Fair - Forecast snowfall amounts are uncertain on Tuesday

Weather Forecast

Overnight and Monday: Strong Northwest winds with 2-3 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 1000 metres.Tuesday: A warm pulse of moisture is expected to bring 5-10 cms to elevations above 1200 metres with strong Southwest winds.Wednesday: Light Southwest winds and another 3-5 cms with freezing levels rising back up to about 1100 metres.

Avalanche Summary

Some pockets of wind slab up to size 1.5 were reported, and sluffing up to size 1.0 continues to be reported from steep terrain.

Snowpack Summary

Wind slabs continue to develop in the alpine and at treeline. Forecast strong Northwest winds are expected to further develop these wind slabs. The recent storm slab continues to be reactive down 30-50 cms at treeline and below. Below freezing temperatures overnight have helped to strengthen the moist surface layers that developed during the weekend warm period. Rising freezing levels forecast during the next pulse of moisture may weaken the old storm slab at lower elevations. The mid-pack is well settled and there are no reported deep layers of concern.

Problems

Wind Slabs

Old wind slabs continue to be reactive to light additional loads. Expect new wind slabs to develop with 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, South.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 4

Persistent Slabs

The recent storm snow continues to settle into a cohesive slab above weak layers and variable old surfaces. This slab may become more reactive during the forecast warm temperatures below treeline.

Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

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