South Columbia Avalanche Forecast Date Issued: Monday, January 14, 2008 at 6:00 PM Valid Until: Thursday, January 17, 2008 Forecast of avalanche danger Tuesday Wednesday Alpine CONSIDERABLE MODERATE Treeline CONSIDERABLE CONSIDERABLE Below Treeline MODERATE MODERATE Travel Advisory The take home message is, although there is not a wide spread avalanche cycle happening right now, there are some serious weaknesses in the snowpack, both in the alpine and below treeline just waiting to catch someone. Although the snowpack seems well settled, the number of surprising avalanche occurrences, especially those at and below treeline, are evidence that things are not as predictable as you might think. Skiers are continuing to pop out small slab avalanches in storm snow in the alpine, predominantly on cross loaded gullies and on convex rolls. More disturbingly, avalanches have also been failing in heavy timber below treeline. These occurrences are highly variable, and happen just when one thinks things are seemingly stable. With clearing skies in the next few days, the temptation to ski bold lines should be countered with a hard look at terrain, and the consequences of being caught in an avalanche. Don’t forget to look up – cornices are getting larger. Avalanche Activity There have been several reports of small avalanches being triggered in the Purcell Mountains involving storm snow near ridge tops, and, more notably, avalanches occurring at and below treeline. The low elevation avalanches are occurring in heavily timbered terrain where avalanche activity would not be expected, and are failing on persistent instabilities deep in the snowpack. Snowpack Soft and hard slabs are forming in the alpine from moderate to high SW winds, varying in thickness from 20 to 50 cm, and in places up to 80 cm. The December 5th rain crust is now down close to a meter in the Purcells, and up to 140 cm in the Selkirks. The midpack is generally well settled. Snow has become moist below 1800 meters on solar aspects in many locations, and will likely form a crust when temperatures cool on Tuesday and Wednesday. Weather A front is passing over BC today bringing 7-10 cm of precipitation and moderate SW winds over the Purcell Mountains this evening, switching to NW by Tuesday. Winds in the alpine are expected to be in the 70-80 kph range on Tuesday, which is ideal for transporting snow onto lee slopes. A ridge of High Pressure will follow in the wake of this front, bringing dryer conditions and cooler temperatures for Wednesday. Issued by:Slyvia Forest / Greg John