South Columbia

There mountains are currently covered with a dangerous snowpack making safe travel difficult. There have been numerous reports of both natural and human-triggered avalanches. Simple terrain is your friend.

Moderate - Timing of incoming weather systems is uncertain on Sunday

Friday: Mostly dry and cool. Treeline temperatures around -6C. Light southwesterly winds.Saturday: Light snow, 5-10 cm. Treeline temperatures around -5C. Light to moderate southwesterly winds.Sunday. Snow, heavy at times. 15-20 cm. Freezing level rising to 1200 m. Strong southwesterly ridgetop winds.

Reports from Tuesday and Wednesday included numerous storm slab and wind slab releases ranging from Size 1-2, as well as several more persistent slab releases ranging from Size 2.5-3. This activity occurred on all aspects and mostly above 1900 m. One persistent slab was skier triggered on the late November layer, down only 60 cm in an alpine location west of the Valhallas.Similar avalanches have been observed daily now for over a week. Expect to see more avalanches where these layers are preserved, such as in sheltered locations in the alpine and treeline elevations and in open cutblocks and gullies below treeline.

70 to 100 cm of storm snow sits on a layer of crust and/or surface hoar from mid-January. The crust is widespread, with the possible exception of high elevation north aspects. The mid-January surface hoar is 5 to 20 mm in size and is likely present at all elevation bands. The recent storm snow fell with strong south winds, producing wind slabs in lee features at treeline and alpine elevations and in open areas below treeline.Deeper in the snowpack, the early-January persistent weak layer is buried 70 to 110 cm deep. It is composed of surface hoar on sheltered slopes and a sun crust on steep solar aspects and is present at all elevation bands. Recent snowpack tests have shown sudden fracture characters with moderate loads and high propagation potential, as well as other signs of instability such as whumpfs and cracking. Yet another persistent weak layer buried mid-December is 100 to 150 cm deep and consists of a facet/surface hoar/crust combination. It is most problematic at and below tree line.A rain crust buried in November is 150 to 200 cm deep. While generally considered dormant, occasional activity has shown that it may react in alpine areas where it is less deeply buried.