Northwest - BC

Date Issued: Friday, 04 February 2011 04:00 PM 
Valid Until: Monday, 07 February 2011 04:00 PM 
Next Update: Saturday, 05 February 2011 04:00 PM 

Smithers & Interior Sections Danger Ratings

					Saturday 		Sunday 			Monday
Alpine 				3 Considerable 	3 Considerable 	3 Considerable
At Treeline 		2 Moderate 		2 Moderate 		2 Moderate
Below Treeline 		2 Moderate 		2 Moderate 		2 Moderate

Avalanche Problem: Wind Slab

Strong westerly winds have created wind slabs in the alpine and at treeline.

Avalanche Problem: Storm Snow

New snow may not bond well to the old snow surface. Storm slabs have formed at lower elevations 
due to above freezing temperatures.

Avalanche Problem: Persistent Slab

Primarily an issue in areas that did not previously avalanche and in areas with a shallow or 
variable snowpack. Watch for re-loading on the old bed surface.

Special Message

The wind increased to strong from the west overnight and the freezing level went up to about 
1400 metres. I suspect that dry natural avalanches are starting in the alpine and running into 
the moist snow below 1400 metres. I have increased the Alpine danger rating to HIGH until we 
get more information from the field.

Confidence: Good

Weather Forecast

Saturday: Cool dry air from the north should move into the region. Expect clearing skies and 
freezing levels around 400 metres. Sunday: The next Pacific system should move onto the coast 
bringing strong westerly winds and moderate to Heavy precipitation. Monday: Light to moderate 
precipitation and moderate southwest winds. Freezing levels should be around 600 metres.

Avalanche Activity

A few reports of natural size 2.5 avalanches that looked moist, but may have started in the dry 
alpine snow. We have not had many observations from the field over the past few days due to the wet 
weather. There has been very limited information on the forums from this region. What are you 
seeing out there?

Travel Advisory

Areas to Avoid:

    * All avalanche terrain during periods of heavy loading from new snow, wind, or rain.
    * North thru East facing wind loaded slopes in the Alpine.
    * Be especially cautious on slopes that did not previously avalanche.

Techniques to Manage Risk:

    * Watch for obvious clues of unstable snow and the presence of wind slabs such as whumfing, 
	  hollow sounds, shooting cracks, or recent avalanches on similar slopes. If observed, back 
	  off to simple terrain. 
    * Ride slopes one at a time and spot for one another from safe locations that are well clear 
	  of avalanche run outs.
    * Use ridges or ribs to avoid pockets of wind loaded snow. 

Snowpack

Freezing level went up to about 1400 metres overnight on 110203. There was 20-30 cms of new snow 
on Thursday. There has been light freezing rain up to about 1200 metres on Wednesday. Previously 
there was faceting of the top 15-30cm of snow, and surface hoar growth in sheltered areas primarily 
at treeline and below. A weak layer of facets or surface hoar can be found down 160-180cm in coast 
areas, and 120-140cm inland. Whumpfing and remotely triggered avalanches indicate that this layer 
could still potentially be triggered.

Prepared by T Riley