Winter only exists for part of the year at best. The meat would have already be rotten and inedible for carnivores when they got to it.
And they don't support your claims. That looks more like a braided stream than a meander. I could not get that video to run on my computer. The flaw may be theirs:
http://www.hqvdos.com/watch/YsQ7hW2fAEs/stream-table-meander-bend-run-emriver-em2.html
Also those are not "sand pans" That is a "stream table". When you make up your own terminology no one will understand what you are talking about. Also you can't directly scale up a stream table. You need to study how fast real meanders form and move:
http://eps.berkeley.edu/~bill/papers/Rowlandetal_ESPL_131.pdf
You are dealing with tens of years at the very least. And if you try to speed up the flow rate all you will do is flood the area and you are back to sheet flow and that will barely start a channel after forming braided streams at best.
Meanders form in slow moving streams. As much as you want them to be they do not form in floods.