We are suspicious of a layer of facets down 40-60 cm that is reactive at treeline and above. We have seen several avalanches fail on this layer over the past week.
20-40cm of recent snow, with sustained and continued moderate to strong winds, has formed widespread slabs at ridgetop and below. In less wind affected areas the storm snow will behave more like a storm slab until it has a chance to settle.
A facet or facet/crust interface 30 to 70 cm down, formed in late January, has been the failure plane for several large avalanches in the region this week. We suspect this is predominantly a problem on south and west aspects, but we have limited information on its spatial distribution.
Sunshine Village reported an out-of-bounds size 2 skier accidental at treeline on a west aspect at 2150 m, where a skier triggered a glade 30 m wide that was 70-100cm deep on facets.
Our field team did a road patrol up Hwy 93 N on Monday and reported the following avalanche observations.
A complex snowpack is emerging in the wake of the recent storm. A common theme is a 40–60 cm slab that is bonding poorly to a layer of facets or a facet/crust combination formed on Jan. 24.
The distribution of this layer (its location) is difficult to pin down, and for now we are concerned about all steep terrain at treeline and above, especially on SE through W aspects, until we learn more about this situation.
A westerly system will move into the region Tuesday night through Wednesday. As this moist air mass approaches, winds will begin to taper, with ridge-top speeds near 30 km/h from the west.
Forecast precipitation amounts range from 5 to 15 cm by Wednesday evening. Freezing levels will rise to around 2,000 meters on Wednesday.
