CANADIAN AVALANCHE ASSOCIATION BACKCOUNTRY BULLETIN _16 DECEMBER, 1996_ _SOUTH COAST & VANCOUVER ISLAND_ _WEATHER:_ Big dump on the north coast but the south coast region from Garibaldi to Duffey Lake area had only trace to light amounts of snow over the weekend. Strong winds on Saturday and Sunday were from the south first and later from the west, now they have swung around to the north west and should stay light to moderate in the alpine. Freezing level will stay at the surface for the Bulletin period and looks like we can enjoy a couple of fine weather days for now. _SNOWPACK:_ The variable strength and direction winds contributed to some new slab formation on various aspects. In the alpine, the generally cool temperatures have slowed the rounding of the previously reported facets deeper in the snowpack but on southerly aspects they seem to be less widespread. This old facet layer is the most serious concern but the distribution is more isolated now. The new slab was giving some easy compression test results. Stability in the alpine is fair, below treeline is good . _AVALANCHES:_ Isolated size 1 avalanches, small slabs up to 10m fracture lines releasing 10-20cm deep. _DANGER:_ _MODERATE_ _TRAVEL ADVISORY:_ Although the overall danger is less than last week, careful use of terrain and good route finding skills are important to put into practice all the time. The first avalanche fatality of the winter happened in the Rockies last week _NORTH COLUMBIA_ _WEATHER:_ In the alpine some heavy snowfalls over the weekend amounted to 40-100cm of snow in different parts of the region. Around Valemount/Blue River got the most but both sides of the Columbia in the Monashee and Selkirks got a good seasonal load too. Alpine winds were moderate to strong from the south and west but winds should ease off now and be light from the north for the Bulletin period. Maximum temperature at 2000m will be in the -10 to -15 range and the strong arctic ridge should remain for most of the week. _SNOWPACK:_ Although the new storm snow was mostly of quite low density the large amounts contributed to significant instability. Much whomphing was heard as settlement occurred. New soft slab has formed in the alpine and this is giving easy results in most field tests, either compression, shovel, burp or rutschblock tests. Mostly it is failing at the new snow interface but the old facets and crust from the 11 November give clean shears and very isolated surface hoar weakness is reported. Overall its quite a tricky Columbias snowpack. Stability is at best fair, particularly in large alpine terrain with potential for deep releases. The most unusual distribution of poor stability is around treeline where isolated pockets of very weak snowpack exist and may still react to remote skier trigger. _AVALANCHES:_ Size 2 and 3's reported in the Valemount area and in Glacier Park, some releasing to the 11 November rain crust. Limited observations during the storm on Sunday. _DANGER:_ _CONSIDERABLE_ trending to HIGH in the alpine and at treeline. _TRAVEL ADVISORY:_ The recent snowfalls have nearly filled in the worst of the lower elevation alder, stump farms and rock pile. So there are excellent conditions from the valley floor up. Watch for the increased danger at treeline and above. _SOUTH COLUMBIA_ _WEATHER:_ A dynamic, vigorous winter storm moved quickly through on the weekend leaving 40-50cm of snow in most parts of the region. Strong winds in the alpine from the south and west accompanied the snow. Temperatures will remain cool with maximums at 2000m around -10degrees or colder. A strong arctic ridge is getting well established and will continue for the Bulletin period. _SNOWPACK:_ New snow and slab instability is the immediate concern. To some extent it has stabilised in the 24h since the storm. But the older weaknesses still exist and give Rutschblock 3 in Kokanee Glacier area and respond to high explosives treatment in Kootenay Pass. Further north, around the Bugaboos, Rutschblocks 4 & 5 were sliding on facets up to 65cm down. Overall snowpack heights are above average in most of the south Kootenays. Now it looks like a good chance for a surface hoar event to get started with a couple of clear nights on the way. Already there are isolated reports of it forming at treeline. _AVALANCHES:_ Lots of size 1 and 2 avalanches, mostly low density with good powder cloud component. _DANGER:_ _CONSIDERABLE_in the alpine and at treeline, _MODERATE_ at lower elevations. _TRAVEL ADVISORY:_ A rash of involvements were reported over the weekend and the first fatality of the year occurred in the Rockies. If you travel alone you must accept that the risk is much greater. Always practice good route finding skills and terrain choice. _ROCKIES_ _WEATHER:_ Huge northerly winds set a new standard over the weekend, temperature are set to plunge for a few days while the arctic ridge prevails and little snow is forecast for the Bulletin period. _SNOWPACK:_ The snow distribution with all that wind was quite varied. For example around Sunshine, west and south aspects got stripped but in Kananaskis, northerly slopes are barren in the alpine. The big winds produced large cornice formation. The northern parts are still kind of lean for snow, with central Banff/Lake Louise about average and southern parts well above average height of snowpack.. Facets continue to grow their square shapes, specially in the north and central parts of the region. Ski penetration to ground was reported in a thin, faceted snowpack near Mt Rundle. Waterton/Westcastle/Fernie seem to be escaping that with glide cracks showing up in the Lizard Range. _AVALANCHES:_ Fatal avalanche on Thursday last week was in a well known skier touring site in Banff National Park. More involvements in avalanches also reported by out-of-bounds skiers. _DANGER:_ _CONSIDERABLE_ _TRAVEL ADVISORY:_ Last winter the Rockies had a very forgiving snowpack. It looks as though the weak faceted snowpack is going to be with us for quite a while yet so very careful route finding is necessary and terrain choice should be very conservative. Frequent slope field tests must be done and with the range of tests available, it is fun. Have each member of you party do a shovel, compression, burp & Rutschblock test and compare the results. The Bulletins will be issued on Monday and Thursday. THIS BULLETIN ALSO SPONSORED BY ALBERTA SNOWMOBILE ASSOCIATION _________________________________________________________________ Contact numbers for the Avalanche Bulletin are: