Tricky conditions are expected to persist for the next few days with touchy new wind slabs expected to develop and a buried weak layer creating the potential for isolated very large avalanches. Conservative terrain selection remains critical.
Summary
Confidence
Moderate -
Weather Forecast
Unsettled conditions are expected to continue on Tuesday with sunny breaks in the morning and light snowfall in the afternoon. 10-15 cm of snowfall is forecast between Tuesday afternoon and Wednesday morning. Alpine wind is expected to be moderate to strong from the southwest and freezing levels are forecast to reach around 500 m in the afternoon. Unsettled conditions are expected again on Wednesday with the potential for both sunny breaks and light flurries. Alpine wind is forecast to be moderate from the southwest and freezing levels should remain around 500 m. There is currently a lot of uncertainty for Thursday but it looks like a storm system could arrive in the afternoon or overnight.
Avalanche Summary
On Monday, a report includes whumphing and a ski cut triggering a size 2 slab which released on the crust layer. Explosives also triggered numerous storm slabs 20-30 cm thick and one stepped down to the crust layer down 40-60 cm. MIN posts from Sunday include whumphing and small skier triggered avalanches on test slopes. On Saturday, a person was fully buried in the Tony Baker Gully near Cypress Mountain. North Shore SAR removed the person from the scene with serious injuries.
Click here for more details. A natural avalanche cycle occurred on Friday which included storm slabs up to 60cm in depth failing on the late-February crust layer. At least one avalanche also stepped down to the deeper mid-February crust layer.On Tuesday, strong southwest wind is expected to develop touchy new wind slabs and thicker old wind slabs may also still be reactive. The weak layers from February are still a major concern and persistent slab avalanches remain possible. It may still be possible for a person to directly trigger a persistent slab or a smaller avalanche could step down. We are entering a low probability, high consequence scenario for very large persistent slab avalanches.
Snowpack Summary
15-30 cm of new snow on Sunday brings the typical storm total 1 m or more since last Wednesday. Strong south and southwest wind during the storm redistributed much of this snow in wind-exposed terrain forming thick wind slabs. The new snow overlies the late-February interface that is composed of a sun crust on southerly aspects and surface hoar on shaded aspects. The recent snow appears to be bonding poorly to this layer and with the cold conditions, the weakness is expected to persist longer than normal for the region. Below this interface is the thick mid-February crust/facet layer which woke up during the natural avalanche cycle on Friday. Below this crust, the mid and lower snowpack appear to be well settled and strong.
rbuhler,
Avalanche Canada
