The Alpine and upper Treeline received a wallop of warm snow and wind, while lower elevations had the "rain hose" blasting hard.
Time will tell on how the persistent slab problem reacts to the additional loading, or if it failed during this recent storm.
See the Avalanche Canada blog post for an info on persistent slab conditions.
65 cm of new snow, warm temps, and strong wind have created slabs. Reactivity/sensitivity of these slabs will decrease with the incoming cold temps. However, this new snow has plenty of warmth and energy stored in it, so the potential for large avalanches remains for several days.
Two persistent weak layers are buried down ~130 and ~170 cm. Last weeks snow, combined with extreme winds, overloaded these layers triggering large, destructive avalanches. Be very suspect of slopes that haven't recently avalanched. These weak layers are still within human triggering depths.
Explosive artillery control on Sunday had excellent results, with widespread avalanches triggered throughout the hwy corridor from sz 2 to sz 4. Of note, avalanche character changed to wet/loose below treeline with the rain and warm temps.
See the Avalanche Canada blog post for info on dealing with persistent slab problems. We are entering the "healing' stage. Avalanches are becoming less likely but the consequence will remain massive for the foreseeable future.
65cm of snow Saturday night, strong/extreme SW winds, and high freezing levels have formed a widespread slab at all elevations.
The Feb 9 and Jan 26 surface hoar (SH) layers are now buried 110-170cm deep, and were stress-tested by the recent warm, heavy storm.
The Feb 9 SH sits over a crust on solar aspects.
The Jan 26th layer is composed of very large surface hoar (up to 40mm), facets, and/or a crust, The largest surface hoar is preserved in sheltered areas below treeline.
Cooler unsettled weather, followed by a stormy Wed.
Tonight Flurries, 5cm. Alpine low -12°C. Freezing level (FZL) Valley bottom. Winds W 15-25km/h.
Mon Isolated flurries, trace amounts. Alp High -12°C. Wind W 25 gusting to 40km/h. FZL valley bottom.
Tues Scattered flurries, 5cm. Alp High -13°C. Wind SW 30 gusting to 60km/h. FZL 500m.
Wed Snow, 25cm. Alp High -7°C. Wind SW 25 gusting to 120km/h. FZL 1100m.
