Sponsored this week by Columbia Breweries SOUTH COAST REGION WEATHER: No need to fly to the sun this Christmas, with the high pressure ridge that has built over BC. The jet stream is hauling warm air out of the South Pacific and flooding it through Western Canada. Even the Yukon is basking in above zero temperatures. Weather balloon readings on the Coast recorded plus 2 at 3200m Thursday. The ridge is predicted to persist for about a week. Expect occasional snow showers through the bulletin period, above zero temperatures right into the alpine, and plenty of problems with fog. SNOWPACK: All this heat is now causing rapid warming of the upper snowpack, with 100cm of isothermal snow at the surface on some southern aspects. The November ice crust down at least a metre is of great concern as upper snowpack strength deteriorates. Avalanche Professionals report the November crust is no longer reactive to shovel tests in some areas, but will still perform when shocked with explosives or cornice fall. A thin layer of facets at the summer ice interface on glaciers may show its face as well. AVALANCHES: Duffy lake observers report natural slab avalanches to size 3.5 on the November crust on South aspects. Virtually all observers are seeing size 1 loose and wet afternoon releases on all aspects. Cornice fall is widespread, and may act to trigger slab avalanches on the crust. DANGER: ABOVE TREELINE - Considerable, increasing as you go inland BELOW TREELINE - Considerable TRAVEL ADVISORY: Cornice fall is likely. Expect increased risk throughout the day, with solar heating on South and West aspects weakening surface slabs. Remember the November crust as you choose your terrain. NORTH COLUMBIA REGION WEATHER: A massive high pressure ridge dominates the weather for the BC interior. Temperatures have been unseasonably warm, even in the alpine. Winds have been light to moderate. The forecast calls for the ridge to slowly weaken, allowing some isolated snowfalls through the weekend. Temperatures will continue to be mild well into next week. SNOWPACK: Although winds have been light, the warm temperatures in the alpine have promoted slab development in open areas. Surface Hoar has formed virtually everywhere, and some areas are reporting surface hoar bands due to overnight layering of valley cloud. The deep November crust problem remains a concern, and the intense solar radiation has people avoiding south quadrant aspects. AVALANCHES: One size 3.5 natural slab in the Revelstoke area was observed on a south aspect, running deep on the crust. Widespread wet loose naturals to size 1 out of south aspects in steeper terrain were being reported. Avalanche activity is expected to taper off, but the November crust will still be down there and should not be forgotten. Cornice failures are becoming common. DANGER: ABOVE TREELINE - Considerable BELOW TREELINE - Moderate TRAVEL ADVISORY: As natural indicators of avalanche danger are not going to be as prevalent this weekend, judging avalanche risk will become increasingly difficult. Shovel tests on the November Crust are now commonly being reported in the hard category. Cautious old skiers and sledders are still choosing terrain with this deep crust instability in mind, and keeping exposure to big alpine terrain features to a minimum. SOUTH COLUMBIA REGION WEATHER: A ridge of high pressure dominates the South Columbias, with unseasonably warm temperatures and virtually no wind for this week. The weather forecast calls for a slow deterioration, with some snow showers through the weekend, but predominantly warm dry conditions until near the end of December. SNOWPACK: Rapid snowpack settlement has promoted improving stability. South aspects are approaching isothermal conditions in surface layers. North aspects have been slower to react to the warm condition. The November crust down a metre or so is still lurking, and has been the sliding layer in a series human triggered avalanche burials. Large surface Hoar crystals blanket the alpine, and will be a problem once we get more snow. AVALANCHES: Two separate human triggered avalanches on the November crust buried victims in the Quartz Creek area near Golden, although no serious injury resulted. Surface releases to size 1 are being reported in all areas on South aspects. Shallow snowpacks closer to the Rockies seem to have more tendency to release to the November Crust than areas further west. DANGER: ABOVE TREELINE - Considerable BELOW TREELINE - Moderate TRAVEL ADVISORY: A false sense of security as natural activity tapers off is the big danger. Two very close calls this week indicate the deep instabilities are still a concern. Sledders are likely at slightly higher risk due simply to the extra weight a sled and rider represents. Avoid grouping up in avalanche terrain if possible, which concentrates weight into a smaller area, allowing stresses to penetrate into deeper layers. ROCKIES REGION WEATHER: The Rockies have been unseasonably warm lately due to a high pressure ridge which has dominated the weather throughout the West. Daytime highs well above zero even in the alpine have been the rule, with light winds out of the northwest. The forecast calls for this trend to continue through the weekend, with the possibility of an arctic outbreak of cold air occurring the end of December. SNOWPACK: The heat is causing surface layers to loose strength, particularly on south aspects. Winds slabs have formed in open alpine areas. The deep crust/facet interface is still a serious concern. AVALANCHES: Naturals to size 3 on south aspects are common in the mountain parks region, running full path on the November crust. Explosive control work earlier in the week along highways in the Lake Louise to Jasper corridor resulted in many large releases out of alpine terrain, running full path as well. DANGER: ABOVE TREELINE - High BELOW TREELINE - Considerable TRAVEL ADVISORY: Natural indicators will taper off this weekend. Those who know the Rockies snowpack well are still very concerned about the crust/facet interface lurking down near the ground. The Christmas holidays are no time to deal with tragedy, so be extra cautious this weekend. Even with clear skies, wind transport and solar radiation will be constantly causing subtle changes in the balance of tensions on this persistent deep snowpack instability.