Waterfalls

The height of a waterfall is often subject to various interpretations. In most cases a waterfall starts with a series of rapids, then goes over a vertical or nearly vertical drop, and ends with a cataract over the debris at the bottom of the vertical drop. The heights given in the table below are those of the highest vertical or nearly vertical drop.

Reversing Falls are phenomena resulting from tidal action. At low tide, the inland waters empty into the sea over a rocky shelf in a waterfall. As the tide rises above the falls, the seawater forces its way against the river flow. The resulting turbulence, in the form of whirlpools, eddies and rapids, makes the falls appear to have actually reversed. Canada's three reversing falls are:

• Saint John River, Bay of Fundy, New Brunswick
• Wager Bay, Ford Lake, Nunavut
• Barrier Inlet, Hudson Strait, Nunavut