Where did the beavers go?

The picture below shows the area of the beaver dam in late September when Paint Branch was flooded:

Contrast that photo with this one which I posted on July 22 from about the same spot:

The beaver dams were damaged by floods a couple of times over the summer, but the beavers always rebuilt. After that September flood, however, they apparently left. I've looked both upstream and downstream for signs of them but haven't spotted any, and I wonder where they went.