For the one and only time in recorded history, Niagara Falls stopped flowing and went dry on March 29th, 1848.
On this day, strong winds pushed ice fields in Lake Erie into motion causing millions of tons of ice to become jammed around the mouth of the Niagara River. This resulted in the channel being blocked completely and stopped all flow over the American and Horseshoe Falls for over 30 hours.
Although the American Falls was intentionally stopped between June 1969 and November 1969 when the U.S. Army Corp of Engineers dammed the falls to study possible actions to remove debris at its base, the Horseshoe Falls continued to flow during this time.
1848 remains the only year that Niagara Falls (the American and Horseshoe Falls) has stopped flowing and went completely dry.