Oh man, I had a good one last night.
I was sitting in a cafe or something in Australia, having lunch or coffee or something with some people. I look out the large windows at the front of the cafe and see an enormous dust storm on the horizon. It was like one of these, only darker:
The storm reached the cafe in just a few seconds. As it approached it started to look green. As it finally reached the cafe, leaves began to slide along the window. I looked out the side windows for another angle. At first I thought it was large vines, but realized that the storm was made of trees, some upside down, some not, floating along at a slow walking pace. We somehow ended up in an RV, and just as we were about to start it up it lifted a few feet off the ground and at a very slight angle, and floated along at the same pace as the trees.
It was a strange sensation. In the dream I knew that everything floating was caused by some unusual wind pattern, probably something that only occurred in Australia. I had never experienced it before, but it was a phenomenon that existed in nature, like a huge dust storm. But though it made sense in the dream, I still kind of knew that it was impossible. Still, I enjoyed the ride.