If it's a waterspout, then why can't we see any waterspout?
I'm guessing that after it left the water, it wasn't strong enough to drag up soil into the spout so as to make it more visible. It was more like an oversized dust devil - strong enough to pick up what amounts to a big balloon since those bouncy houses are inflatables. The kids had broken bones though.
Thanks.A rachmanus on those kids.