Tornado? Nah, who knows, without a wider angle shot and the mountains being removed from the pic its too hard to tell. I'm no expert, but i would say some sort of inflow/updraft. Really need a wide angle shot to reveal whats going on.
This is over the Toolangi state forest at approx. 4.25pm.
Much, much further south than you guys were.
I'm really glad I got out yesterday, this was one of the more interesting/memorable things I've seen in my short career.