Natural large avalanches on 93s

Banff Yoho & Kootenay National Park

CMcGee , Wednesday 3rd February, 2021 6:40PM

Witnessed two large avalanches mid-day when the sun was starting to shine and when the wind picked up. One was a small size 3 that started as a small loose slide from the ridge top, but then stepped down much deeper (old PWL?) at around 2000m. The other was a 2.5 that also started as a loose dry, but then trigged a slab in the storm snow and continued to the valley bottom. The wind was affecting the snow at and above TL. We observed many size 2.5's from the past 24hrs in steeper alpine features.

Snow conditions were: Deep powder. Weather conditions were: Windy, Cloudy, Sunny. We avoided: Alpine slopes, Steep slopes, Convex slopes.

Avalache Conditions: 30cm + of new snow, or significant drifitng, or rain in the last 48 hours. Slab avalanches today or yesterday. Whumpfing or drum-like sounds or shooting cracks.

Avalanche

Witnessed two large avalanches mid-day when the sun was starting to shine and when the wind picked up. One was a small size 3 that started as a small loose slide from the ridge top, but then stepped down much deeper (old PWL?) at around 2000m. The other was a 2.5 that also started as a loose dry, but then trigged a slab in the storm snow and continued to the valley bottom. The wind was affecting the snow at and above TL. We observed many size 2.5's from the past 24hrs in steeper alpine features.

Source: Avalanche Canada MIN