An unusual persistent weak layer makes steep and convex terrain features particularly dangerous at this time.
Summary
Confidence
High -
Weather Forecast
WEDNESDAY NIGHT: Clear skies and cold temperatures.THURSDAY: Dry, becoming cloudy. Freezing level around 600 m. Light northeasterly winds.FRIDAY: 10-15 cm new snow. Freezing level around 500 m. Moderate westerly winds.SATURDAY: 2-4 cm new snow, clearing. Freezing level around 500 m. Light southwesterly winds.
Avalanche Summary
On Monday, search and rescue responded to an avalanche in the Mount Seymour backcountry, which resulted in a fatality. The avalanche occurred on a steep feature at treeline elevation
(see photo here). Avalanche professionals involved in the rescue indicated wide propagation consistent with a persistent slab problem. The crown depth was variable - 40 to 100 cm, indicating there was also wind loading in that area.On Friday and over the weekend, there is evidence of a widespread avalanche cycle up to size 2.5. These avalanches showed impressive propagation, with some being triggered remotely (from a distance) and some occasions stepping down to a 50 cm deep crust layer.
Snowpack Summary
40-80 cm of recent storm snow lies above a crust. The new snow has bonded poorly to this crust and natural and human-triggered avalanche have been noted on this interface. The reactivity of this layer appears to be worse in the south of the region (i.e. the North Shore Mountains) since this part of the region has seen more snow and it has consolidated into more of a slab. Unusually for this region, we expect this layer to remain reactive for some time into the future. New sun crusts may be found near the surface of south-facing aspects, while wind slabs may be found in exposed terrain. The lower snowpack is settled and strong.
jfloyer,
Avalanche Canada
