South Rockies

Fair - Due to limited field observations

A series of weak short waves move over the southern half of the province this weekend bringing high cloud and very little in the way of precipitation. Temps remain mild, just a few degrees below 0 at 1500m. Winds look to be meek, whispering out of the NW @ 5 - 15 km/h. This pattern continues through the weekend. The models show a bit of a change next Wednesday, but forecast details that far out are sketchy at best.

Throughout the weekend numerous highly destructive persistent deep slab avalanches involving basal facets and depth hoar occurred in the alpine and ran to valley bottoms (check out the Avalanche Image Gallery under the Library tab for some photos). These highly destructive avalanches remain possible with heavy triggers, such as airborne sled impacts and cornice falls, in thin areas on variable slopes peppered with tree's and rocks.

In Elk Valley North and the Crowsnest, the average snowpack depth at treeline is 150 cms. In Elk Valley S and the Flathead the snowpack depth is closer to 2 m. Surface hoar is continuing to develop on sheltered slopes at all elevations combined with near-surface facets at lower elevations and surface crusts on sun-exposed slopes. A well settled and strong snowpack sits on weak basal facets and depth hoar, which seem to be fairly widespread throughout the region. This deep persistent weakness recently became active again with warm temperatures, but cooler temperatures have once again reduced the sensitivity to triggers. Highly unpredictable glide cracks are also opening up, primarily on slopes with smooth ground cover. These full-depth gaping 'crevasses' could release without warning or act as a significant terrain trap.