December 27, 2002 SOUTH COAST REGION WEATHER: Watch Out! 140 cm of new snow in 36 hours by Friday at Whistler - Merry Christmas! The strong westerly flow which brought this snow also brought strong winds in alpine areas, but fortunately freezing levels remained in the valley bottom throughout. A series of storms is forecast to track onshore over the weekend, bringing snow and more strong winds. Predictions are a bit uncertain, but expect another 10-20 cm through the weekend, possibly more. SNOWPACK: With the enormous volume of new snow that fell, rapid loading and instabilities within this new snow are a serious concern. Significant windslab formation was observed in areas above treeline. Initial indications following the peak of the storm are for a stabilizing trend within the new snow ^Ö but with surface hoar, crusts and facets lingering in the middle of the snowpack the likelihood of triggering large avalanches remains significant. Areas below treeline are now well beyond the threshold depth for avalanching - with a tender layer of surface hoar just under this recent storm, a renewed view of forested areas is recommended. AVALANCHES: Widespread avalanching on Boxing Day (Dec 26), natural, human and explosive triggers. One full burial from a small slope below treeline near Blackcomb resulted in a successful rescue. FORECAST OF AVALANCHE DANGER UP TO MONDAY EVENING (DEC 30) ALPINE: EXTREME TREELINE: HIGH BELOW TREELINE: HIGH TRAVEL ADVISORY: Backcountry travelers should approach this weekend with caution. Significant changes have occurred to the snowpack leading into the weekend ^Ö conservative decisions are recommended. Build your knowledge of conditions progressively and keep your distance from avalanche terrain. NORTH COLUMBIA REGION WEATHER: Xmas and Boxing Day storms were good to the Interior Ranges, with 30-50 cm of new snow falling in the North Columbia region. Freezing levels have remained well below the valley bottoms and winds have varied from strong to light. Friday^Òs forecast indicates another significant storm to cross BC late Friday, hopefully giving another serious injection of snow. More snow to follow through the weekend. SNOWPACK: A significant layer of surface hoar was buried on Xmas day and now sits within the upper meter of the snowpack. Tests and observations indicate this layer to be very weak with avalanches failing easily at this level. As more snow accumulates and the storm snow becomes denser with windloading, expect avalanches to continue failing on this surface hoar. Deeper in the snowpack, a layer of crust/facets/surface hoar also remains a concern, and the potential for large avalanches is significant ^Ö especially in shallow, or uneven snowpack areas. AVALANCHES: Widespread avalanching was observed on Thursday and is expected to continue given the weather forecast. FORECAST OF AVALANCHE DANGER UP TO MONDAY EVENING (DEC 30) ALPINE: HIGH (periods of EXTREME) TREELINE: HIGH BELOW TREELINE: CONSIDERABLE TRAVEL ADVISORY: This is a weekend for careful traveling in the backcountry. If the forecast snowfall materializes, then certainly the avalanche hazard will increase and travel in any avalanche terrain cannot be recommended. In the absence of additional snow over the weekend, the many slopes may not avalanche naturally but will be ripe for human triggering. Monitor weather and snowpack conditions closely this weekend. SOUTH COLUMBIA REGION WEATHER: The storm that passed after Xmas has left 30-50 cm in it^Òs wake, depending on your location. Strong SW winds were observed on Dec 26, but fortunately the freezing levels remained well below the surface. Weather forecasts on Friday are indicating another significant storm to cross the region Friday and Saturday, possibly leaving a welcome but destabilizing dump of snow behind. Strong winds will accompany this storm. SNOWPACK: Most areas report a significant layer of surface hoar that was buried on Xmas day by this most recent storm. As of Friday, the new snow remained light enough that little slab formation was observed. However, with strong winds observed on ridge tops and more on the way, expect further windslab formation over this weekend. These windslabs will be failing on the surface hoar at all elevations. In certain locations (thinner snowpacks), buried crusts and facets remain a concern in the lower snowpack and the potential for large avalanches on this layer remains. AVALANCHES: Numerous explosive and human triggered avalanches were observed on Thursday. FORECAST OF AVALANCHE DANGER UP TO MONDAY EVENING (DEC 30) ALPINE: HIGH TREELINE: HIGH BELOW TREELINE: CONSIDERABLE TRAVEL ADVISORY: If the forecast materializes as predicted, then we will enter the first significant avalanche cycle of the season. With low elevation snowpacks still relatively thin, large avalanches to valley bottom are not expected, but human triggering at treeline and above is a significant concern this weekend. Travel with caution and make conservative decisions. KOOTENAY BOUNDARY REGION WEATHER: The Christmas snowstorm has left 20-40 cm behind in the southern part of the province. Strong winds were observed on Boxing Day but temperatures remained well below freezing. On Friday, a deep low pressure center is forecast to track over this region, with the possibility of more heavy snow. If this materializes, it looks to be accompanied by high winds and a slight rise in temperatures. Watch closely! SNOWPACK: Most areas report a significant layer of surface hoar that was buried on Xmas day, now with upwards of 40 cm sitting above it. As the load increases with additional snowfalls and windloading, this instability will grow more active. Reports on Thursday indicate the buried surface hoar to be very sensitive, so we forecast the potential for human triggering to be on the rise over the weekend. AVALANCHES: Widespread small avalanches observed on Thursday, expect the sizes to increase on Friday. FORECAST OF AVALANCHE DANGER UP TO MONDAY EVENING (DEC 30) ALPINE: HIGH TREELINE: HIGH BELOW TREELINE: CONSIDERABLE TRAVEL ADVISORY: If the forecast materializes as predicted, then we will enter the first significant avalanche cycle of the season. With low elevation snowpacks still relatively thin, large avalanches to valley bottom are not expected, but human triggering at treeline and above is a significant concern this weekend. Travel with caution and make conservative decisions. SOUTHERN ROCKIES REGION WEATHER: The dry spell continues to plague this region ^Ö Fernie received 15 cm from a storm over the Christmas period, but east of here into the Crowsnest remains dry. On Friday morning a significant low pressure system is tracking east, very close to the US border. We are all optimistic that this may produce significant snowfalls in the Southern Rockies region, probably accompanied by the characteristic strong winds of the Crowsnest. If this happens, then expect the bulk of the storm to be occurring on Friday night and Saturday morning. SNOWPACK: In the Fernie area, the 15-20 cm of snow over Xmas covered a significant layer of surface hoar which formed in the days prior. Even the blanket of new snow - with wind - has been producing small avalanches on this surface hoar layer. Any significant loading on this layer will produce avalanches. Conditions in the Crowsnest region again will relate entirely to windloading. Even with completely dry slopes nearby, gullies filled with weak facets can easily become windloaded and produce avalanches. AVALANCHES: Numerous small avalanches near Fernie, failing on buried surface hoar 20 cm down. FORECAST OF AVALANCHE DANGER UP TO MONDAY EVENING (DEC 30) ALPINE: HIGH in Fernie ^Ö CONSIDERABLE in Crowsnest TREELINE: HIGH in Fernie ^Ö MODERATE in Crowsnest BELOW TREELINE: CONSIDERABLE in Fernie ^Ö LOW in Crowsnest TRAVEL ADVISORY: Avoid steep, windloaded terrain near the Fernie area. If the forecast storm materializes, then a widespread avalanche cycle will occur and all slopes should be considered suspect. In the Crowsnest region, sledders have only recently begun to reach alpine areas with enough snow for snowmobiling. Stay away from steep, windloaded gullies as these are one of the few places where avalanches can be triggered right now. Leeward slopes are particularly dangerous, so note wind transport patterns carefully.