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Avalanche Forecast

Dec 17th, 2011–Dec 18th, 2011
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low

Regions: Purcells.

For more information on the effects of incremental loading, please check out our forecasters blog by clicking the tab at the bottom of the forecast page.

Confidence

Fair - Forecast snowfall amounts are uncertain on Sunday

Weather Forecast

A cold front is expected to move through the interior on Saturday night. This trailing cold front will follow in the wake of the warm air that we saw on Saturday and is forecast to bring another 10 cm by Sunday morning to the North and West regions of the Monashees and Cariboos. Less snow is forecast for the South and East areas of the Selkirks and Purcells. Freezing levels are expected to fall back to valley bottoms as cold air and moderate to strong Northwest winds move over the interior. Sunday is expected to be mostly dry but probably still overcast. Clearer and colder weather should be across the interior on Monday. The next Pacific system is expected to start moving in from the coast on Tuesday. It is a little early to determine intensity and timing for the next system.

Avalanche Summary

No new avalanches reported.

Snowpack Summary

A cold front is expected to move through the interior on Saturday night. This trailing cold front will follow in the wake of the warm air that we saw on Saturday and is forecast to bring another 10 cm by Sunday morning to the North and West regions of the Monashees and Cariboos. Less snow is forecast for the South and East areas of the Selkirks and Purcells. Freezing levels are expected to fall back to valley bottoms as cold air and moderate to strong Northwest winds move over the interior. Sunday is expected to be mostly dry but probably still overcast. Clearer and colder weather should be across the interior on Monday. The next Pacific system is expected to start moving in from the coast on Tuesday. It is a little early to determine intensity and timing for the next system.

Avalanche Problems

Wind Slabs

This problem is changing from old wind slab on a non-persistent layer, to new soft wind slab on a recently buried surface hoar and/or crust layer. Remember that old wind slabs exist, and that new more touchy wind slabs are developing.

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 3

Loose Dry

As the new storm snow builds up above the recent surface hoar we could see sluffs that entrain enough snow to bury or injure a person. When the storm snow settles or is wind blown into a slab it may propagate wider avalanches.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible

Expected Size: 1 - 2

Persistent Slabs

Highly variable snow depths make this very difficult to predict. Weaker thin spots on convexities or around protruding rocks/clumps of small trees may be likely trigger locations for deeper avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely

Expected Size: 2 - 5