Storm slabs over the Jan. 24 surface hoar layer are becoming reactive and are a developing problem.
The deep, persistent layer remains dormant. Thick-to-thin transitions remain an area of uncertainty.
Storm slabs have started to form and are sitting over harder surfaces and/or surface hoar in many places. This is a developing problem that could catch users off guard, especially in areas with wind effect.
Lake Louise and Sunshine patrol reported ski cutting a few small size 1 wind-slabs in immediate alpine lee areas, most being 15-20cm thick. Late in the day Saturday Visitor safety responded to an avalanche near Boom Lake. One skier went for a short ride and lost equipment. They had minor injuries and was evacuated by helicopter. More reports from Yoho of similar-sized avalanches. All appear to have been running on surface hoar buried Jan 24.
Up to 15cm of storm snow from the last 4 days now cover the Jan 24 layer, which is surface hoar and crust. Expect that same 15cm to be wind effected in the alpine. A deeper surface hoar layer (Jan 3) lies 50–60 cm down, but there have been no recent avalanches. Basal crust and/or facets exist in thin snowpack areas, but overall, this year's deeper snowpack is stronger than usual.
Cloud increasing overnight into Sunday, followed by up to 5 cm of new snow during the day. Additional snowfall of around 5 cm is expected through Monday, for a total of up to 10 cm, though amounts vary and 10 cm represents the upper end of current forecasts. Continued mild seasonal temperatures, with valley temperatures near 0 and ridge temperatures around −8. Strong SW remain elevated through the period.
