Avalanche Forecast - South Columbia   
Date Issued   Thursday, 02 February 2012 5:29 PM   	   	
Valid Until    Friday, 03 February 2012 11:00 AM

Danger Rating: 
	
Alpine:			3 - Considerable - Dangerous avalanche conditions. Careful snowpack evaluation, 
                                   cautious route finding and conservative decision making essential.
Treeline: 		2 - Moderate - Heightened avalanche conditions on specific terrain features. Evaluate 
                               snow and terrain carefully; identify features of concern.
Below Treeline:	2 - Moderate - Heightened avalanche conditions on specific terrain features. Evaluate 
                               snow and terrain carefully; identify features of concern.

				Saturday 		Sunday
Alpine 			2 - Moderate 	2 - Moderate
Treeline 		2 - Moderate 	2 - Moderate
Below Treeline 	1 - Low 		1 - Low

Confidence: Good - -1

Wind Slabs

Wind slabs may look smooth, feel stiff, and have a hollow sound under foot. They're most likely 
to be found on N-E aspects, and below ridgecrests.

Storm Slabs

Storm slabs may be susceptive to rider triggers. You're most likely to trigger a storm slab in 
steep and/or unsupported/convex terrain.

Cornices

Large cornices have formed. They may become weak with rising freezing levels. You should give them 
a wide berth whether traveling near them or far below them. Failing cornices have the potential to 
trigger large avalanches on the slope below.

Travel and Terrain Advice

    * Make observations and assess conditions continually as you travel.
    * Dig down to find and test weak layers before committing to a line.
    * Give cornices a wide berth when travelling on or below ridges.
    * Stay off recent wind loaded areas until the slope has had a chance to stabilize.

Prepared by swerner

Avalanche Summary

Very little natural slab avalanche activity to report. Reports indicated natural sluffing from steep 
rocky terrain features size 1-2. Several reports of rider triggered avalanches occurred on various 
aspects @ elevations of 1400-2100m. This tell me the storm slabs are still reactive to lighter loads. 
Also to note, cornice failures have been occurring naturally producing size 2. Explosive cornice 
control done Wednesday produced a size 2.5 on the slope below. I suspect cornice fall may increase 
under forecast alpine sun, possibly creating large slab avalanches on the slopes below.

Snowpack Summary

Storm slabs up to 60cms thick have formed. They seem to be settling out quick, but still slow 
sensitivity to rider triggers; especially on steeper slopes and convex rolls. Wind slabs have formed 
on North through East slopes in the alpine and at treeline. Buried below seems to be a fairly settled 
mid-pack, with a couple lingering layers.We continue to monitor the January 13th surface hoar/facet 
layer, and the January 28th interface. Recent snowpack field tests have shown generally moderate 
results, including resistant planar shears. These layers are getting stronger; but they may become 
reactive with the forecast warming. The average snowpack depth at 1700m is 2-3 m.

Weather Forecast

A strong ridge of high pressure will persist through the forecast period bringing dry conditions, 
sunny skies, and warmer temperatures. On Friday/Saturday freezing levels may rise to 1000m in the 
afternoon, then drop to valley bottom at night. Ridgetop winds may generally be light from the South. 
Maximum alpine temperatures near -1. Sunday brings alpine sun, developing valley cloud and inversions.