South Columbia Avalanche Forecast

Date/Time issued: Wednesday, March 08, 2006 at 6:00 PM
Valid until: Friday, March 10, 2006

Forecast of avalanche danger 

 	           Wednesday  Thursday	     Friday
Alpine	        Moderate    High      Considerable	
Treeline        Moderate    High      Considerable	
Below Treeline   Low       Moderate     Moderate	

Travel Advisory: Well here we are in March faced with a mid-winter storm that 
will transform the mountains into an unreal playground on Thursday and Friday, 
but also kick the avalanche danger to High. It is the classic caveat that we all 
must consider while riding in the backcountry after a storm. All the good pow 
tempts us to ride steep and beautiful lines, but we must wait for the snowpack 
to stabilize. We suspect that on Thursday a natural avalanche cycle will occur 
meaning that a number of steep slopes will run at treeline and in the alpine. 
Some of these slides may be large running on the Feb 20 weak layer buried 40 
to 70 cm deep. On Friday, the natural slides should abate, but triggering an 
avalanche will remain probable in steep terrain.

Avalanche Activity: We suspect that it will be easy to trigger slides in terrain 
steeper than about 35 degrees on Friday and in some locations it may be possible 
to remotely trigger a slide.

Snowpack: There are a number of weak layers buried in the snowpack that may 
release with the storm snow or your weight through Friday. In some places there 
was a weak layer of facets or surface hoar buried on March 5. It is up to 20 cm 
deep. A little deeper and more widespread is the Feb 20 facet and surface hoar 
layers. These layers gained significant strength in the last week, but still are 
popping clean in many stability tests. On south facing slopes the snowpack is more 
complex with numerous sun crusts in the top metre of the snowpack.

Weather: Snow amounts Wednesday night and Thursday morning will vary over the 
forecast region from east to west. In the Dogtooth Range, expect 20 cm of snow 
while areas near Nakusp could see over 30 cm. A consistent theme to the storm will 
be wind. Upper elevation ridgeline winds may reach 90 km/hr until the cold front 
passes. This is expected on early Thursday morning. On Thursday and Friday temperatures 
at treeline are forecast to be around -7. An additional 10 cm of snow is expected. By 
Friday, the sky should be mostly cloudy with scattered light snow showers.

Issued by: Greg Johnson