A major avalanche cycle occurred on Wednesday, and this will continue on Thursday. Natural avalanches ran over the ice climbs Masseys and Guinness Gully near Field, as well as 75% of the avalanche paths in the Kootenay highway and reports of widespread activity in Bryant Creek. Avoid all avalanche terrain on Thursday.
With Thursday's new snow, a 60-120 cm slab of dense, warm snow now sits atop mid-pack facets and depth hoar at the ground. This will fail as both wet and dry slabs with wide fracture propagations, and the natural avalanche cycle will continue.
20-40 cm of new snow will fail as a surface slab, both wet and dry, and as a wind slab at higher elevations. Thursday is a storm day, and new snow avalanches are expected throughout the day - this conditions should improve relatively quickly over the coming days as the temperature cools.
Wet snow and rain to at least 2200 m has resulted in an isothermal snowpack in many areas below treeline. This snow has no strength and will avalanche easily and run like water into gullies and depressions. Avoid all gully features below treeline.
A widespread avalanche cycle occurred starting midday on Wednesday, with avalanches starting at all elevations and numerous paths running to the valley bottom. Masseys ice climb ran mid-day, burying half of the first pitch, as well as all of the ice climbs on Mt Dennis, including Guiness Gully. Widespread avalanche activity was also reported in Bryant Creek and in the Mt. Assiniboine area. Expect this condition to have been everywhere in our region.
15 cm of new snow and/or 13 mm of rain has fallen in the past 24 hours, up to 2200 m in the region, triggering a widespread avalanche cycle and causing dramatic snowpack settlement (see images). A dense slab 50-100 cm thick overlies a weak, facetted snowpack which is now isothermal below treeline. Natural and human triggered avalanches are almost certain in all areas.
In the wake of Wednesday's warm front, another push of snow and rain will cross the region on Thursday, with 20-40 cm of snow expected and freezing levels at 2200 m, but on a cooling trend. This will result in rain below treeline, mixed snow and rain at treeline, and new snow in the alpine. Winds look to be in the moderate range.
