March 29th 1848, the falls ran dry for around 40 hours due to ice blockages. What a sight to see!
A slight correction to your post.
Yes, in 1848 it ran dry due to ice.
What you pictured was the 1969 event that dried the falls. This was done by the Army Corps of Engineers.
Two events separated by over a century gave visitors a look at Niagara Falls without the Falls. And it may happen again soon.
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From June 25, 1969, to November 25, 1969, the U.S. Army Corps of Engineers
built a 600-foot dam across the American Falls so geologists could study the rock formations underneath and try to dislodge boulders that had accumulated at the bottom, cutting off its length. The dam took 27,800 tons of rock and soil to divert the water.
As the geologists worked, a walkway was built to accommodate tourists eager to see the dry landscape. When the geologists finished, the dam was knocked down. It took less than a day for the Falls to do the rest, flowing normally later that night. (Scientists decided to leave those boulders alone, thinking it was better not to mess with nature.)
If you think this was a sight to behold, there’s a good chance it will happen again in our lifetimes. The state of New York
intends to dewater the Falls at some point in the coming years to repair two 115-year-old pedestrian bridges that lead to Goat Island. Only the flow of the American Falls will be diverted, which makes up roughly 15 percent of the water. While the remaining flow will be 15 percent stronger, visitors will still see a portion dewatered. New York State just has to get the $26 million in
needed funding to make it happen—something nature accomplished for free back in 1848.