Kootenay Boundary Avalanche Advisory

Date Issued
    Sunday, 16 January 2011 03:00 PM 
Valid Until
    Wednesday, 19 January 2011 03:00 PM 
Next Update
    Monday, 17 January 2011 03:00 PM 

 
		            Monday 	        Tuesday 	    Wednesday
Alpine 		        4 High 	        3 Considerable 	3 Considerable
At Treeline 		3 Considerable 	3 Considerable 	2 Moderate
Below Treeline 		3 Considerable 	2 Moderate 	    2 Moderate

Avalanche Problem

Wind Slab: Strong W-SW winds have created deep and weak wind slabs in exposed terrain at 
all elevations.

Storm Snow: Continued snowfall combined with rising temperatures has created upside down 
snow conditions. This has resulted in a dense slab overlying a weak surface hoar layer – 
prime slab avalanche conditions. 

Persistent Slab: Several buried persistent weak layers exist throughout the snowpack. 
Avalanches starting in the storm snow could step down to one of the deeper layers, or 
they could wake up with additional loading or heavy triggers. 

Special Message

Mild temperatures, continued precipitation, and moderate-strong ridge top winds are keeping 
the avalanche danger elevated on Monday. Backcountry travel is not recommended without 
professional level guidance and safety systems.  

Confidence: Fair

The general trend is for drier and cooler weather early this week. This should help to 
gradually lower avalanche danger.  

Weather Forecast

Monday: Light snow in the morning, clearing in the afternoon; 5-10cm. Freezing level 
dropping from 1800m to around 1300m. Winds are moderate to strong from the W-SW. 
Tuesday and Wednesday: Mainly cloudy with occasional sunny breaks. Freezing level 
lowering to valley bottom. Winds are moderate from the W-NW.  

Avalanche Activity

A widespread natural avalanche cycle has been ongoing for the past couple days and will 
likely continue into Monday with more snow and high freezing levels. Several reports 
involve avalanches (up to size 3) stepping down to the early January surface hoar layer, 
which is 60-80cm deep in most places. 

Travel Advisory

Areas to Avoid:

    * All avalanche terrain unless you have professional level guidance and safety systems in place.
    * Exposed north through east facing slopes or cross-loaded terrain where weak wind slabs exist.
    * Avoid exposing yourself to the run outs of large overhead avalanche paths.
    * Large open slopes, especially in areas where the snowpack is thin or variable in depth, 
	  where triggering deeper persistent weak layers is possible or step-down avalanches are more 
	  likely.

Techniques to Manage Hazard:

    * Stick to SIMPLE, low-angle slopes that are not threatened by overhead avalanche terrain. 
	  Might be a good time for mellow, protected glades or “boondocking” in the meadows.
    * Choose your route carefully. Avoid crossing avalanche terrain if possible, and if you must 
	  cross an avalanche slope do so one at a time with a spotter in a safe location. 

Snowpack

Up to 60cm of storm snow sits on a buried layer of surface hoar. Strong W-SW winds have 
redistributed the new snow onto lee slopes in exposed terrain at all elevations. There are 
several buried surface hoar and crust layers in the upper pack. Many of these layers continue 
to give moderate or hard “pops” results in snowpack tests and remain a concern for larger 
triggers and step-down avalanches. A crust buried on Dec 14th can be found locally in the south 
of the region.