What is the name given to a strong tide that pushes up the river, against the current?
Correct answer: Tidal bore
aqualung
There's one on the river Severn in Wales
Schulzie
No comma needed.
Arabella
The Petitcodiac River at Moncton, New Brunswick, Canada has a tidal bore due to its closeness of one of the highest tides of the Bay of Fundy. It is pretty scare watching a river "go backwards".