dementomstie It was done with an air compressor filling up an empty tank which was also connected to a quick release switch. When the quick release switch is triggered the pump stops filling the tank and at the same time the air from the tank is released from the tank shooting the sawdust into the air.
At least that's how they explained it on Mythbusters.
chumbucket i have become death, destroyer of wood dust
plug Much better than igniting bottle rockets in your buddy's ass. So many things that could've gone wrong, but they pulled it off. I'm anxiously awaiting the video of an imitator who screws it up and ignites their house.
dead_cat Oh, giant exploding canister, where have you been all my life?