The winds have arrived, contributing to windslab development and cornice growth at upper elevations. In addition, at lower elevations, the Jan surface hoar is becoming increasingly reactive as the load builds. Being mindful of what is both underfoot and overhead while traveling through elevation bands will be key this week.
SW winds have increased into the moderate-to-strong range with extreme gusts, building wind slabs in lee terrain. These winds have redistributed up to 30 cm of recent snow over the past week, creating reactive wind slabs at treeline and above.
A 20-40 cm slab (increasing with incoming snow) over the Jan. 24th surface hoar layer could catch users off guard at treeline and below. Check the snowpack often and monitor the behavior of the slab above this weak layer closely. Recent activity has been between 1600 and 1900 m.
Reports of a wind-initiated natural avalanche cycle to size 2 at upper elevations was noted on Monday.
At lower elevations, we continue to receive reports of increased reactivity of the surface hoar problem. Monday, a field team reported widespread whumphing and cracking on this problem. Over the past week, there have been several skier-triggered avalanches on this problem to size 1.5.
New wind slab development is expected at treeline and above as Moderate to strong South and West winds redistribute 25 to 30cm of surface snow onto lee slopes.
The Jan 24 layer (surface hoar/crust) is down 30-40 cm at treeline and has been reactive in some areas in Yoho and Kootenay – Dig down and check for this layer before committing to steep terrain
Snow will taper Monday evening as a brief clearing trend moves in Tuesday. This will be short-lived, as another frontal system will move into the region Wednesday, bringing more precipitation. At the moment, there is a large discrepancy in forecasted snowfall amounts, ranging from 5 to 30 cm by Thursday afternoon. Winds will remain elevated through this period, and temperatures will hold near -7°C at 2000m.
