Niagara Falls were formed when glaciers receded at the end of the Wisconsin glaciation (the last ice age), and water from the newly-formed Great Lakes carved a path through the Niagara Escarpment en route to the Atlantic Ocean. More than six million cubic feet (168,000 m³) of water falls over the crest line every minute in high flow, and almost 4 million cubic feet (110,000 m³) on average.

American Falls

In Winter