North couloir on Thar, Coquihalla Avalanche.

Size 2.5/3 avalanche yesterday while skiing the North couloir on Thar in the Coquihalla. We rappelled the upper exposed sections then skied down. Two skiers were caught. One was able to stop himself after 20-30 feet of sliding. The other pulled his airbag and slid all the way until the point where this picture was taken. Both skiers remained on the surface and are okay. The crown line was 2- 2.5 feet deep at sections and thinner at others and spanned the entire couloir. A surprise wind slab was to blame, sitting on the old wind effected layer from a week and a half ago. As we skied the higher, steeper sections of the couloir nothing jumped out at us. The snow was a dust on crust, it was sloughing off as one would expect while skiing higher angle terrain. However as we got to the last portion of the couloir where it is much lower angle it seems as thought the snow built up and was loaded at one point. This was triggered by the upper skier, who was able to stop himself. However the lower skier was not and slid with the avalanche all the way to the toe of the avalanche. about 80m from the trees on the other side of the valley. No one was injured.