North Columbia

Keep watching for signs of slab formation and reactivity in the new snow and be ready for solar radiation to promote instability on Tuesday.

Moderate -

Tuesday: A mix of sun and cloud. Winds light from the southwest. Alpine temperatures around -17.Wednesday: A mix of sun and cloud. Winds light from the east. Alpine temperatures of -12.Thursday: Periods of snow delivering approximately 10-15 cm of new snow. Winds light from the southwest, becoming strong. Alpine temperatures of -4.

Reports from Saturday and Sunday include observations of numerous Size 1-2 storm slabs being triggered both naturally and with ski cutting, as well a small number of remote triggers and slides stepping down to involve old wind slabs. These soft slab avalanches have been noted running fast and entraining large amounts of loose snow. A mid-storm interface observed at approximately half the depth of the new snow has been particularly reactive.As for Tuesday's outlook, fresh storm slabs should be expected to remain sensitive to light triggers, especially where they overlie weak layers present at our previous surface and where winds have promoted slab formation. Loose dry avalanches are another hazard to consider in areas with deeper accumulations of new snow. These should not be underestimated in terrain where they have the potential to entrain significant mass.

Around 25-40cm of new, low-density snow from the past few days has buried a range of surface conditions that developed last week. These previous surfaces include older wind slabs on a wide range of aspects, sun crust on steep solar aspects, faceted snow, as well as surface hoar found on sheltered open slopes in the days before the storm. The new snow is beginning to form a bond to these surfaces, but touchy conditions at this interface as well as at mid-storm interfaces should still be expected over the short term. A persistent weakness buried mid January is now down 50-80 cm and consists of buried surface hoar in sheltered areas, and/or widespread faceted old snow. It has generally stabilized but may be sensitive to triggering in isolated areas where buried surface hoar is preserved.Another surface hoar/facet persistent weakness was buried mid-December and can now be found down 110-130 cm. It has become inactive in the south of the region, but may remain reactive in the northern part of the region near Blue River and Valemount. Read the Cariboo forecast for more information.