From bulletin@avalanche.ca Wed Mar 1 19:44:04 2006 Date/Time Issued: March 01, 2006 at 1800 Valid Until: March 03, 2006 South Columbia Region Forecast Area: This forecast includes the southern Columbia Mountains, including the Monashee, Selkirk and Purcell Mountain ranges. This region includes the eastern side of the Okanagan Valley from Osoyoos to Enderby, areas south of Highway 1 from Sicamous to Golden, areas west of the Columbia River between Golden & Kimberley, and areas north of Kaslo and Castlegar. This forecast region does not include Glacier National Park. Forecast of avalanche danger beginning Wednesday, March 1, 2006: Day:\Wed. p.m.\Thursday\Friday Alpine:\High\High\High Treeline:\High\Considerable\Considerable Below Treeline:\Considerable\Considerable\Moderate Travel Advisory: A huge amount of storm snow has arrived in the last week; up to 25% of the snowpack height in some areas. The storm snow came in several distinct periods of moderate to heavy snowfall and unfortunately this has resulted in one or more easy shears. Immediately before this addition of new load, we had a long period of cold weather that destroyed the strength of the upper third of the snowpack, and did serious damage to the midpack strength. Natural avalanche activity will decrease Friday, but the potential for human triggering is unfortunately not going to leave us just yet. The good news is with all this wonderful new snow, very conservative terrain choices will still yield top quality skiing and reasonable sledding. Try to avoid steeper slopes altogether for now and stay below treeline and away from big open slopes or avalanche paths and their runouts. Southern aspects will remain unstable due to solar radiation so these should be avoided, particularly in the afternoon. Avalanches: Avalanche activity was widespread on Monday and Tuesday, with smaller loose releases and larger slab releases. On Wednesday, natural activity had begun to decrease in frequency and size but was still seen throughout the region. Ski cutting and explosives continued to reliably trigger slabs to size 2.5. Natural activity will be less on Thursday, primarily occurring from cornice fall and from heating on solar aspects in the afternoon. The potential for human triggering will be with us until at least the weekend. Snowpack: Up to 75cm of storm snow, containing easy shears was still evident Wednesday, sits on top of a layer of weak facets caused by the recent cold snap. Windslab is present in the alpine, and south slopes have a surface crust during the mornings. The bond with the facets below is still very weak. The midpack is still relatively strong. Shallow snow areas are the exception, where the midpack strength has been eroded and then stressed the by rapid loading from the storm snow. The two weak layers in the lower snowpack are unchanged. Weather: Light snowfall and moderate south winds can be expected Thursday. The freezing level will rise to 1500 meters. Friday, the weather will cool, and light snowfall will continue. Issued by: Evan Manners