Lizard-Flathead

Wednesday was a day of very active avalanche conditions. A bit more snow and a lot more wind in the forecast means storm slabs will remain primed for human triggering.

Moderate - Forecast snowfall amounts are uncertain

Wednesday night: Increasing cloud and flurries bringing a trace to 5 cm of new snow. Strong southwest winds.Thursday: Cloudy with continuing flurries bringing about 10 cm of new snow. Moderate to strong southwest winds. Alpine high temperatures around -6, increasing overnight as freezing levels rise to 2000 metres.Friday: Mainly sunny with increasing cloud and light flurries in the evening. Strong to extreme southwest winds. Alpine high temperatures to about 0 as freezing levels rise to 2200 metres.Saturday: A mix of sun and cloud with easing flurries a trace of new snow. Strong to extreme southwest winds easing in the afternoon. Alpine high temperatures around -5 with freezing levels returning to about 1500 metres.

Reports from the Fernie and Corbin areas on Wednesday showed numerous storm slab releases, both natural and explosives-triggered. Slabs ranged from 20-80 cm in depth, depending on wind effect, with sizes generally from size 1.5-2. Size 2 would be classified as 'large'. These all occurred from about 1700-2000 metres and were focused on north to east aspects due to strong southwest winds.Another recent notable avalanche was a size 2 human triggered avalanche on December 2nd in Cornice Bowl north of Fernie. It occurred on a northwest facing feature at 2300 m and ran on a crust layer. There are good photos in this MIN report.

Tuesday night's storm brought 30-40 cm of new snow to the region. The new snow has buried an old snow surface that was noted earlier in the week for a cover of large, weak surface hoar crystals as well as hard wind slab and some sun crusts. Beneath the new snow and old surface, the snowpack has been stuck in early season conditions, hovering at roughly 100 cm of depth in alpine areas and much less at lower elevations. See the snow profile in our field team's MIN report for a visual representation of the pre-storm snowpack here. Aside from storm slabs now blanketing the surface, a primary concern is the combination of weak facets and crusts in the bottom half of the snowpack. The crust is most prevalent at and above treeline and is likely most problematic on north-facing features, especially those that are large and planar in nature. A layer of large surface hoar can also be found at similar depths in some areas, as found in a recent MIN report here.