Reversing Falls of Saint John is a waterfall located in the St. John River at Saint John, New Brunswick, just before the river enters the Bay of Fundy. The name refers to the fact that the river’s current sometimes runs backwards up the falls.
The waterfall is formed as the river valley becomes a narrow gorge. At low tide, the river falls 14 feet (3.7 meters) in going through this gorge to the harbor below. At high tide, a bore (rushing tide) sweeps in from the bay and makes the level of the harbor water 14 feet (3.7 meters) higher than the level of the river. The current through the gorge then flows upstream and up over the falls.
