Sea To Sky

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.

Moderate -

Unsettled conditions are expected to continue on Tuesday with sunny breaks in the morning and light snowfall in the afternoon. 5-10 cm of snowfall is forecast between Tuesday afternoon and Wednesday morning. Alpine wind is expected to be moderate to strong from the southwest and treeline temperatures are forecast to be around -10C. 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 treeline temperatures should remain around -10C. There is currently a lot of uncertainty for Thursday but it looks like a storm system could arrive in the afternoon or overnight.

On Sunday, a skier triggered a size 1 storm slab on a northeast aspect. The terrain was described as steep and rocky, and the slab was 50 cm thick. Sluffing was also observed from steep terrain features. On Saturday, natural avalanches up to size 2.5 were observed on a variety of aspects with crowns up to 45cm in depth. Explosives triggered avalanches and cornice failures up to size 2.5 on a variety of aspects with crowns averaging 20 to 40cm in depth. Sadly, there was an avalanche fatality west of Whistler near Gin Peak/Hanging Lake on Saturday. This avalanche occurred on a west-facing feature at treeline, size is estimated to be 2 to 2.5, approximately 80 m wide with a 100 cm crown. Click here for more details.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.

15-20 cm of new snow on Sunday brings the typical storm total to 50-80 cm since last Wednesday. Strong south and southwest wind during the storm redistributed much of this snow in wind-exposed terrain forming wind slabs up to 150 cm thick. The new snow overlies the mid-February and late-February interfaces which may sit quite close together in the snowpack. The late-February interface consists of wind crust and hard sastrugi in wind-exposed terrain, and up to 20cm of facets in sheltered areas. The mid-February interface consists of a thick rain crust which extends into the lower alpine, a sun crust on steep solar aspects, and in many places, a layer of facets overlying the crust. Recent observations suggest a poor bond between the recent snow and these weak layers. Below these layers, the mid and lower snowpack are well settled and strong.