If you were a pro whale your coins would be moving around stealthily. I've seen loadsa posts panicking about dumps when big coin numbers move. Was there ever a subsequent dump? Nope.
Big coin numbers moving isn't indication of a dump.
The characteristics of how they move however may be something a clever program that monitors the blockchain could detect, and it would be easy to test the accuracy of such a program on historic data.
Stealthily moving coins still requires transactions in the blockchain.
The idea isn't to panic. The idea is to sell some before other people panic when the dump happens and then buy back at say 5% lower value, increasing the coins you are holding for free.
I suspect such a thing may be possible. And some traders may already be doing it.
Any such program, like I said, should be easy to test on historic data.