South Rockies Avalanche Forecast

Date/Time issued:
    Wednesday, January 30, 2008 at 4:00 PM
Valid until:
    Friday, February 01, 2008 at 12:00 AM
    
  	               Thursday     	  Friday
Alpine 	        4 - HIGH 	        4 - HIGH
Treeline        3 - CONSIDERABLE    3 - CONSIDERABLE
Below Treeline 	3 - CONSIDERABLE 	3 - CONSIDERABLE

Special Message:   

My concerns are: 
1. Slabs in the alpine and at treeline; 
2. Isolated slabs and loose snow avalanches below treeline; 
3. At and below treeline in shallow snowpack areas, one or more facet on crust persistent 
   weak layers (PWL) buried early in the season.

Travel Advisory

Up to 90cm of recent new snow, significant fluctuations in temperature, and strong winds were 
reported over the last couple of days and I suspect significant variability in avalanche 
conditions and danger in this region. Temperatures have been cold and the new snow dry and 
light, both factors that inhibit slab formation and triggering of avalanches. However, I am 
reluctant to drop danger ratings in light of the amounts of recent new snow and wind and a 
forecast that indicates more snow and wind is coming (to the west side of the divide anyway). 
In areas that received lesser amounts of new snow (say less than 30-40cm) and lighter winds in 
the last storm, local danger may be lower than in this forecast. Forecasting the track and 
intensity of storms in the current situation has proven difficult; there has been and I expect 
will continue to be local variation in snowfall, wind, cloud cover, and perhaps temperature. This 
means local variation in avalanche conditions and danger are also likely. I recommend a high 
degree of caution in all avalanche terrain for the next couple of days. Staying on simple, low 
angle terrain is what I’d do until I was quite certain things have settled down. Continue to 
monitor the persistent weak layers that exist in your region and minimise risks by avoiding areas 
where these layers are known or suspected to exist. Click here to read in depth discussion 
regarding these layers.

Avalanche Activity

Avalanches were reported throughout the region. A natural slab up to 300cm thick from a windloaded 
area yesterday was the most recent of several notable slides that occurred on both sides of the 
border in recent days. Be wary if temperatures increase or if the sun comes out and warms the snow.

Snowpack 

Recent storm snow is settling on the west side of the divide and being affected by strong winds on 
the east side. This storm snow lies on a variety of surfaces, most of which have characteristics 
that suggest poor bonds are likely. Instability is evident in windloaded areas and it could increase 
rapidly in severity and extent if temperatures rise (especially if accompanied by snowfall or wind) 
or if solar radiation warming occurs.

Weather

Recent storm snow is settling on the west side of the divide and being affected by strong winds on 
the east side. This storm snow lies on a variety of surfaces, most of which have characteristics 
that suggest poor bonds are likely. Instability is evident in windloaded areas and it could increase 
rapidly in severity and extent if temperatures rise (especially if accompanied by snowfall or wind) 
or if solar radiation warming occurs.

Issued by: Karl Klassen