North Rockies - BC

Date Issued: Thursday, 20 January 2011 06:00 PM 
Valid Until: Sunday, 23 January 2011 06:00 PM 
Next Update: Friday, 21 January 2011 06:00 PM 

This is not an avalanche forecast. It is a report of recent and current conditions. This report 
can serve as a starting point for planning trips but additional current, local information is 
required.

Avalanche Problem: Storm Snow

There has been over 100cm of new snow in the past week. The latest storm this week on Thursday and 
Friday will have deposited 30-40cm of new snow at upper elevations alone. Expect to find touchy 
windslabs on northeast, east and southeast aspects in the alpine and at treeline.

Avalanche Problem: Persistent Slab

Well developed depth hoar exists at the base of the snowpack. There is at least one mid-snow pack 
persistent layer of concern too.

Avalanche Problem: Cornice

Significant winds have created large and tender cornices.

Special Message

The lower snowpack in this region is generally very weak. Expect to see elevated avalanche danger 
as additional new snow adds a significant load on top of the weaker lower pack. 

Confidence: Poor, Very few information inputs from this region.

Weather Forecast

A further 15-20cm of new snow is possible for Friday. A brief ridge of high pressure is expected 
to build for Saturday and Sunday giving generally drier conditions.

Avalanche Activity

Some natural activity has been reported from southerly aspects from the middle part of this week. 
As the load on the weaker lower snowpack increases expect to see a marked increase in natural 
avalanche activity.

In many areas bordering to the south of this region (Cariboos, Monashees and Selkirks) there have 
been numerous recent unusually large and destructive avalanches which have run beyond their 
traditional runouts. Use this as food for thought when choosing terrain to ride in the short term.

Travel Advisory

It's all about diligent terrain selection and safe travel practices at the moment.

Areas of Concern: 

    * Wide open slopes of 30 degrees or greater in steepness. Slopes that have a convex shape. 
	   Slopes that have thin spots like rocky outcrops etc. 
    * Areas with exposure to open slopes above, especially to those with cornices. A cornice 
	   releasing and landing on a slope would be considered a significant trigger for some of the 
	   deeper buried weak layers.

 Techniques to Manage Risk:

    * Analyze your route thoroughly from a safe area so you can better anticipate hazardous areas. 
	  Look for options to eliminate or reduce your exposure. 
    * Ride or cross slopes one at a time and spot from safe locations. Regroup well away from 
	  avalanche slopes in dense timber or on high ground.
    * Be aware of other users in the area and how their activities might affect you or how your 
	  activities might affect them.
    * If bogging down, stop spinning your track before you dig through and hit the weak layer 
	  below.  

Snowpack

In general, the the lower snowpack is weak and faceted. The most widely reported feature is the 
size and prevalence of depth hoar at the base of the snowpack. In places, this may be accompanied 
by a November rain crust. It is possible that a mid-pack surface hoar layer from early December and 
middle of January could be found in sheltered locations. Total snowpack depths are highly variable, 
but average around 100-150cm in sheltered treeline locations.

Prepared by Mark Bender