Avalanche Forecast

Moderate - Due to the number of field observations

Wednesday: Isolated flurries (up to 5cm possible). Light southerly winds. Alpine temperature near -5.Thursday: 5-10 cm snow. Moderate south west winds. Alpine temperature -6. Friday: 10-15cm of snow. Moderate south west winds. Alpine temperature near -5. More information can be found in the Mountain Weather Forecast.

On Tuesday we received preliminary reports of an avalanche involvement in the north of the region near Clemina creek. The information we have indicates the avalanche ran on a north facing aspect near 1900m. A widespread natural avalanche cycle to Size 4 was reported on Tuesday, at all elevations and aspects. Many large avalanches were running on the mid December persistent weak layer, down approximately 150cm. 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. Conditions will remain primed for human triggered avalanches, with the potential for some surprisingly large avalanches given how many persistent weak layers exist in the snowpack.

60-90 cm of snow fell from Sunday through to Tuesday and temperatures warmed up to -1 at tree line on Monday. Winds were strong to extreme from the south, building cornices and creating wind slabs on lee (down wind) slopes.The new snow sits on a complex snowpack and there are three main 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.