South Columbia

New snow continues to add to the developing storm slab. The next Pacific storm should arrive on Thursday.

Fair - Timing, track, or intensity of incoming weather system is uncertain

Overnight and Wednesday look pretty dry, with light Southwest winds and daytime freezing levels rising up to about 800 metres. The next Pacific system is forecast to hit the coast early Thursday morning and move quickly inland. Expect strong Southwest winds and 10-20 cm of snow during the day and another 10-15 cm by Friday morning. Freezing levels are expected to rise quickly on Friday to at least 1500 metres in the North of the region and up to 2000 metres in the South combined with strong Southwest winds. The storm should continue through Saturday.

There were numerous size 1.0 natural and skier triggered avalanches, and explosives triggered avalanches up to size 2.0 reported on Monday. In some areas pockets of wind transported snow were easy to trigger at ridgetops where they were sitting on a hard crust.

Thin new slabs may not be bonding well within the storm snow. Pockets of wind transported snow at ridgetops may be easy to trigger where they are sitting on the crust that formed last week. The new storm slab is up to 40 cm thick and sits above a variety of old surfaces. The old surfaces include the crust that formed last week, a new layer of surface hoar that developed during the clear weather late last week, and in some places wind slabs that developed smooth hard surfaces. Deeper in the snowpack the mid-January surface hoar remains a concern. It can be found down between 40 and 100 cm. In some locations it has reportedly gained quite a bit of strength, but elsewhere it is still producing sudden (popping) failures in snowpack tests. This spatial variability means we'll have to keep an eye on it for a while yet. The mid-December surface hoar layer is now 80 to 140cm below the surface and has become unlikely to fail, the storm at the end of the week should be a good test to see if it will become active again.