New snow needs to settle before extreme sports
After nearly a week of snow storms avalanche potential is considerable in the back country so winter sports enthusiasts need to exercise caution over the coming weekend.
“The mountains have hit the reset button and we need to do the same with our expectations of what is safe to ride,” commented Matt Peter, forecaster with the Canadian Avalanche Centre. “There have been avalanches reported both within the storm layers as well as at the initial storm interface, the Jan. 4 layer.”
Up to 60 centimetres of snow was deposited over the last few days across the Kootenay Boundary regions. Peter said that the new snow will need several days to settle and stabilize.
Consistent southwest winds have redistributed the new snow (dramatically in some areas) to create widespread windslabbing on lee and open features in the alpine and exposed treeline, according to Peter’s report. Where the wind has been strongest, windslabs are much lower on slopes than normal.
This layer consists of small facets, surface hoar (up to 12mm) in sheltered treeline and below treeline areas and sun crust on steep south and west facing slopes. The bonds with the facetted snow are improving while the surface hoar / sun crust interface is weak. There are reports of sudden planar shears (fast & clean) in compression tests and propagation likely results in extended column tests on the preserved surface hoar.
Peter recommends that skiers and sledders:
- Stay off recent wind loaded areas until the slope has had a chance to stabilize;
- Use ridges or ribs to avoid wind loaded snow.