Niagara Falls formed over 12,000 years ago at the end of the Ice Age when the downpour of water from melting ice wore away rick layers to form the structure that exists today. The first people to witness the falls were most likely the Native Americans living in the regions surrounding the horseshoe falls. The area was later annexed by the French when Father Louis Hennepin reached the Niagara River in December 1678.

Niagara Falls Runs Dry Day celebrates March 29, 1848, the day when a bitterly harsh winter gave way to ice on Lake Erie, which gradually broke away. Strong winds drove the ice to the mouth of the falls, thus suspending the flow of water for over 30 hours. Some of the first to notice the unusual event were nearby mill owners who realized that their water wheels had stopped rotating. Soon, hoards of people inched their way to the falls to witness the odd event. They were able to witness, for the first time since the forming of Niagara Falls, absolute silence in place of a roaring waterfall. Several people ventured across the riverbed, finding old ammunition used in the Battle of Chippawa in 1814. At night, hundreds of people reportedly made the trek across the riverbed with lit torches in their hands.

Niagara Falls remained dry until the afternoon of March 30, when the winds reversed their direction and everything returned to the way it was.

Resource: https://nationaltoday.com/niagara-falls-runs-dry-day/