South Columbia Avalanche Forecast Date/Time issued: Friday, February 15, 2008 at 6:00 PM Valid until: Monday, February 18, 2008 at 6:00 PM Next Scheduled Update: Monday, February 18, 2008 ---------- S. Selkirks & S. Monashees ---------- Saturday Sunday Monday Alpine 3 - CONSIDERABLE 3 - CONSIDERABLE 3 - CONSIDERABLE Treeline 3 - CONSIDERABLE 3 - CONSIDERABLE 3 - CONSIDERABLE Below Treeline 2 - MODERATE 2 - MODERATE 3 - CONSIDERABLE Confidence: Danger Trend: Fair, Timing: Fair.There is likely to be high variability in the snowfall this will affect avalanche danger. Currently we are thinking Monday will be the warmest day. Warm sunny weather will cause danger to rise on south facing slopes. Primary Concerns: * Wind Slab: Where the storm snow exceeds 20cm there will be avalanches related to wind slabs on north and east facing alpine terrain, especially Saturday. * Deep Slab: Several recent avalanches stepped down to the January 26 and Dec. 5 deep weak layer. Warming temps mean you might be able to trigger one of these layers with a snowmobile from a thin spot on a south-facing slope beginning Sunday. Travel Advisory Issued: Fri, Feb 15 Next Scheduled Update: Mon, Feb 18 A fairly intense front will bringvariable amounts of snow to the region. Snow could be quite lightinthePurcells butsubstantialon the west side oftheSelkirks.The real fun begins as a warm Pacific high pressure system moves over the region. Sunny warm weather beginning on Sunday, but digging in on Monday will loosen up the snowpack. The reappearance of avalanche activity associated with the deeply buried layers from late January and the really deep layer from December means that you should avoid south-facing slopes steeper than 30 degrees as soon as the sunny weather hits. Avalanche Activity Issued: Fri, Feb 15 Next Scheduled Update: Mon, Feb 18 Most of the avalanche activity over the past couple of days has been within the recent storm snow. This activity mostly oneast and north-facing alpineslopesis rapidly diminishing as the storm snow stabilizes. Activity on the January surface hoar layer is also declining. The bad news is additional snowfall, followed by significant warm weather on Sunday and Monday will weaken the January layer. So over the course of this forecast you should watch for Windslabs on north and east slopes on Saturday. Sunday and Monday south-facing slopes at treeline and below will be the most threatened spots. A larger trigger such as a sled could trigger a very big avalanche if you hit the sweet spot. The Monashees south of highway 6 is probably the location with the most potential for triggering the deep weak layer from December. Snowpack Issued: Fri, Feb 15 Next Scheduled Update: Mon, Feb 18 Persistent layers (surface hoar, along with facets and sun crust in some locations) from Feb. 4th and Jan. 26th are now buried on average a little under 1m and a little over 1m, respectively. The early December persistent weak layers are an ongoing concern deep in the snowpack in the Purcells as well as in the Monashees south of highway 6. In the Selkirks we are not seeing the same problems with this layer. Weather Issued: Fri, Feb 15 Next Scheduled Update: Mon, Feb 18 An intensefront will deliver5-25 cmof the good stuff by Saturday morning. Saturday there will be clouds with local flurries in the wake of the front. Winds will drop from moderate southwest to light northwest. Sunday a warm high begins to build in, becoming stronger overnight to Monday with alpine temperaturesapproaching the freezing mark by Monday mid-morning. Issued by: JK