North Columbia

Heavy snowfall and rising temperatures will cause a widespread avalanche cycle. It's best to avoid all avalanche terrain, free from overhead hazard.

Moderate - Intensity of incoming weather systems is uncertain

Tuesday: 10-15cm of snow Monday overnight into Tuesday, with another 5-15 cm snow during the day. Moderate south-easterly winds. Alpine temperature near -6. Wednesday: Isolated flurries (up to 5cm possible). Moderate southerly winds. Alpine temperature near -5.Thursday: 5-10 cm snow. Moderate south winds. Alpine temperature -6. More information can be found in the Mountain Weather Forecast.

A widespread natural storm slab avalanche cycle to Size 3.5 was reported on Monday, at all elevations and aspects. On Saturday, a human-triggered Size 2.5 avalanche was reported near 2300m on a south west aspect in Glacier National Park. See the MIN report for incident details. Expect natural avalanche activity to continue through Tuesday, with the potential for some surprisingly large avalanches given how many persistent weak layers exist in the snowpack.

15-35 cm of storm snow fell Sunday into Monday and temperatures warmed up to -1 at tree line. The new snow sits on a complex snowpack and there are three active weak layers that professionals are monitoring:1) 80-110 cm of storm snow sits on a crust and/or surface hoar layer from mid-January. The crust is reportedly widespread, with the possible exception of high elevation north aspects. The mid-January surface hoar is 5 to 20 mm in size and was reported at tree line elevations and possibly higher. 2) Deeper in the snowpack, the early-January persistent weak layer is 110 to 140 cm below the surface. It is composed of surface hoar on sheltered slopes as well as sun crust on steep solar aspects and is found at all elevation bands. Snowpack tests show sudden fracture characters and signs of instability such as whumpfs, cracking and avalanches. 3) Another weak layer buried mid-December consisting of a facet/surface hoar/crust combination is buried 120 to 170 cm deep. It is most problematic at and below tree line.