Class 3 avalanche on London Ridge

Performed a column test atop London ridge. Minimal stress initiated a quick column collapse 50cm deep around 1800m. As we skied away from our test area toward a safe ridge, a skier in our group triggered a class 3 slab avalanche commencing on the lee side of the ridge. The mountain side let go and thundered down the valley about 1km in distance. Two skiers in a seperate group across the valley, 600m away, narrowly missed the slide by 30 seconds, purely by chance, as they crossed the slide path. The last sight we had of them, their tracks, disappeared at the avalanche path. So we skied down and began a 2 person search, all the while calling out. No response. After we cleared about 125m down from their tracks, they came out of the bush. We stopped our search. No one was hurt.