Kootenay Boundary

A slab up to 100 cm in depth is consolidating above a volatile weak layer which has recently produced large avalanches. Travel carefully at and below treeline with intention to avoid convexities, steep features and rocky outcroppings.

Moderate - Forecast snowfall amounts are uncertain on Tuesday

SUNDAY: Flurries, accumulation 5-10cm / Light west wind / Alpine temperature -4MONDAY: Cloudy with scattered flurries / Light to moderate southwest wind / Alpine temperature -2TUESDAY: Flurries, accumulation 5-10cm / Light south wind / Alpine temperature -2

On Thursday a skier triggered a size 3 avalanche just after entering the east face of Evening Ridge at 2000m near Nelson. The avalanche released to ground and the late November crust was likely involved. The avalanche caught and carried the skier for over 300 m, resulting in significant injuries. Subsequent avalanche control in the area produced 2 additional size 2.5 avalanches. Also on Thursday, a natural size 1.5 persistent slab avalanche likely failing on the mid-December surface hoar was observed on a west facing feature during the heat of the day.On Monday another avalanche failing on the mid-December interface was triggered remotely from 10 m away as a skier approached a rocky outcropping on an east/southeast facing feature around 1900 m, MIN report with photos here. A skier also triggered a small storm slab on a west facing feature around 2200 m Monday which was suspected to have failed on the late December surface hoar. On New Years Eve a skier was involved in an avalanche on an east facing treeline feature at Kootenay Pass. A recent crown profile has shown that this avalanche failed on the late November crust/facet interface.

Warming alpine temperatures this week began to moisten the snow surface on steep southerly aspects and surface hoar once again covers the present surface in many locations. Up to 10cm of new snow now sits on the previous surfaces. Storms last week produced 25 to 50 cm of low density snow that was accompanied by moderate to strong winds generally out of the south. This snow rests on a surface hoar layer buried late in December surface hoar. Between 50 and 100 cm below the surface you'll find a layer of well-developed surface hoar buried mid-December. This layer is most pronounced at treeline, but it is present below treeline also. The overlying slab is now deep and is gaining cohesion with time and continued warm temperatures, as evidenced by recent avalanche activity listed above.Two laminated crusts created by twin rain events in late November lay just below the December 15th interface, 70 to 110 cm below the surface. Facets may be found sandwiched between the two crusts and have been observed above the uppermost crust too. In shallow rocky terrain the mid December Surface Hoar and the late November crust seem to be reacting together which is a volatile combination.