January 1, 2001 Happy New Year from the Canadian Avalanche Centre! NOTICE OF UNUSUAL AVALANCHE CONDITIONS: Valid until further notice. This season avalanche professionals between the Inner Coast Mountains and the Rocky Mountains have observed snowpacks that are unusually weak. The combination of below normal snow depth and low temperatures has produced layers of facetted grains and surface hoar with a low strength. These types of weak layers can persist for a long time, and the avalanche danger will increase with every load of new snow onto this weak base. The present snowpack is less stable than in most other years and remarkably different from the snowpack at the same time last winter. Back country users will have to pay much attention to snowpack structure and strength during this winter. SOUTH COAST REGION WEATHER: Daytime highs climbed above zero in the alpine. Winds remained light, while skies were overcast. A ridge of high pressure persists, causing any Pacific disturbances to either track well north or break apart as they come onshore. A series of weak storms will track inland throughout mid week, resulting in brief snow showers with sunny breaks between. Late in the week, there is a chance of more significant moisture. SNOWPACK: A crust sits at the surface, although it is so warm below 1500m that the snow surface remains moist even overnight. Rapid settlement is occurring. The lower snowpack is less affected by the heat, continuing to represent a significant weakness from the buried facet layer near ground. Trigger zones for this deep weakness will be concentrating in the shallow areas such as when you traverse into a slope, or around, rocks, stumps, and convex terrain features found out in the open slopes and on glacial moraines. AVALANCHES: Observers report scattered natural activity, including one that stepped to the lower facet layer, as well as consistent results to size 2 with explosive testing. By Monday, very little activity could be found, except solar radiation related sluffing to size 1 on steep south slopes. FORECAST OF AVALANCHE DANGER UP TO THURSDAY EVENING (JAN 4th) ALPINE ^Ö Moderate TREELINE ^Ö Moderate BELOW TREELINE ^Ö Low, increasing mid day TRAVEL ADVISORY: Shaded high elevation slopes may have lingering shears in the surface slab. Shallow transition zones will continue to be suspect, as the trigger forces will be more likely to reach the faceted weakness at the base. Expect higher hazard inland from the coast, in areas like the Coquihalla. NORTH COLUMBIA REGION WEATHER: Cloudy skies, light south winds, and moderate temperatures predominated the last weekend of the millennium. Virtually no snow fell despite several weak systems tracking inland. A ridge of high pressure persists over the interior, diverting these systems north. The ridge will flatten mid week, allowing one system to bring snow to the northern parts of the region. Freezing levels will rise. Significant moisture may materialize late in the week, although forecasters had low confidence on this Monday, so check weather forecasts daily. SNOWPACK: The storm snow from last week has settled and gained strength. The mid snowpack has been gaining strength, but buried surface hoar continues to fail in snowpack tests, usually breaking with moderate force 70 to 100 cm deep. The lower snowpack is still an ugly mess of weak facets and depth hoar, and this weakness will be slow to gain significant strength. Don^Òt begin to trust deep facet layers to quickly! AVALANCHES: Natural activity has tapered off. Occasional human triggering is still being reported throughout the region. Propagation is now quite often observed, including one slide in Pine Pass which failed in the facets, propagated half a kilometer wide and killed two snowmobilers. Near Revelstoke, one observer also reported feeling a subsidence on the flats which triggered two remote slides above, one 500m away. FORECAST OF AVALANCHE DANGER UP TO THURSDAY EVENING (JAN 4th) ALPINE ^Ö Considerable, weak zones persist TREELINE ^Ö Considerable BELOW TREELINE ^Ö Moderate TRAVEL ADVISORY: We may learn to hate these periods between snowfalls when natural activity tapers off and all we have are reports of occasional human triggered events failing on the deep weak facet layer, now propagating widely. Shallow snowpack areas represent the greatest risk of acting as trigger zones. The answer is conservative terrain use. Ask a Rockies snowpack veteran how long it can take for deep facets to gain strength. SOUTH COLUMBIA REGION WEATHER: The South Columbias were virtually without wind the whole weekend, while temperatures remained mild and skies were predominantly high overcast. Weather forecasters predict this will continue, although winds may pick up a bit. The freezing level will continue to march upward toward the alpine. SNOWPACK: A sun crust is forming on solar aspects well into the alpine. Surface hoar is forming everywhere, and this process will continue. This often sits on a temperature crust, potentially making it an ideal failure/bedding layer once it gets buried by the next snow. Generally, the snowpack continues to be less than average depth, with the weak faceted base the most significant weakness across the entire region. AVALANCHES: No activity observed, although most observers report widespread whumphing and settlements significant enough to shake the snow off trees quite a distance away. The tiger sleeps. FORECAST OF AVALANCHE DANGER UP TO THURSDAY EVENING (JAN 4th) ALPINE ^Ö Considerable TREELINE ^Ö Considerable BELOW TREELINE ^Ö Moderate TRAVEL ADVISORY: When the South Columbias get a significant snowfall, expect them to come alive with avalanche activity. Right now, we remain much like a Rockies snowpack, shallow, with a weak faceted base. Avalanche Awareness Days are January 12th and 13th this year. Check your local media for events in your area. ROCKIES REGION WEATHER: Light winds, reasonable temperatures, and once again, very little snow occurred during the last days of year 2000. The forecast calls for winds to pick up and temperatures to rise well above zero in the valley bottoms. By Wednesday, some areas may see some snow, with the greatest chance in the North Rockies around Jasper and the Columbia Icefields. SNOWPACK: The snowpack continues to be unusually shallow, and comprised primarily of weak facets and depth hoar. Some areas are still reporting ski penetration to ground mid mountain. The Christmas storm left enough snow behind to form a surface slab in some alpine areas. Further south, more snow can be found, although even in areas like Fernie, the snowpack is still generally less than a metre in depth. AVALANCHES: Explosives use often produces releases to ground due to the weak faceted structure of the snowpack. One slope near Fernie released after 15 sledders had high pointed, burying two to their waists and damaging their sleds. Remote releases, where people feel a subsidence and see avalanches release some distance away, continue to be commonly reported. On December 31, one ski tourer in the Crowfoot Pass area reported one remote release that broke nearby a metre deep, causing him to conclude that hazard at that local was significant enough for a conservative retreat. Near Jasper, avalanche activity is most significant right at treeline, in one case breaking in a kilometer and a half wide band above and below treeline near the Columbia Icefields. FORECAST OF AVALANCHE DANGER UP TO THURSDAY EVENING (JAN 4th) ALPINE ^Ö Considerable, trending to High with warming TREELINE ^Ö Considerable, trending to High with warming BELOW TREELINE ^Ö Low TRAVEL ADVISORY: Expect the rising temperatures to degrade surface strength, perhaps to the point where natural releases begin again. Ice climbers may want to resign themselves to an early alpine start this week, due to the increasing hazard as daytime temperatures climb. If overnight lows remain above zero, expect hazard to begin to increase more rapidly. If we get big snows late in the week, we^Òll get big avalanche action as well.