That's what I was getting at with a couple of my previous posts. We have a creek running through our bottom paddock.
That creek can come up from a trickle, or even a dry creek bed, to a raging torrent in minutes - literally. That's how and why cars get washed off the road if they're silly enough to try and cross it. I drive a 4WD with all the off-road goodies including raised suspension etc - and I would NOT try to drive along the road when that creek is flooding across it.
In the floods in January 2011, that gentle, babbling brook of a creek was roaring 2 metres deep, and with enough force that it literally peeled back the bitumen off the road surface over quite a distance, and washed it up and over so that when the water receded, it looked like a perfect surf wave frozen in time, on the other side of the road. Like a peeled back sardine can lid.
Most of the creeks around here can do that - and it can be quite sudden, as the flood surge comes down out of the hills we have all around Brookfield. Once that ground is saturated, and the runoff channels into all the creek beds, then we can get situations just like that creek that flooded in the centre of Toowoomba shown on all the news footage last year. Tragic but spectacular. Most of the locals here are used to it, and know where to avoid.
The whole point being that Kholo Creek and Little Ugly Creek would have done just that on that fateful weekend. And why I'm in the "washed down to the bridge" camp. If Allison had been placed (or dropped) AT the bridge, surely she would have been washed away into the Brisbane River with the flood surge coming down the creek? Unless she was somehow tied to the bridge supports, which I'm pretty sure she wasn't....