In 1848, the people around Niagara Falls got treated to their own big-budget disaster movie special effect.
One night, in very early spring, a local man noticed that things were a bit quiet in his neck of the woods. Too quiet! He walked in the direction of the loudest thing in town – the falls. When he arrived, he saw that the river had been reduced to a low trickle. By morning, people woke to see that the entire Falls had run dry. People’s reactions were mixed. Some were sure it was a sign of the end of the world. Others were excited, and ran down into the basin of the river to grab artefacts that had been buried by the water. One business even did a little landscaping, blasting away some rocks that were known to damage boats on the water.
The explanation came a few hours after the water stopped flowing. Ice had piled up in Lake Erie to the point where it had choked off all the water flowing to the falls. The ice jam kept the water from flowing for two days. When it jostled loose, people scrambled up onto the shore again, as the river came thundering back over the falls. Edited from What happened the night Niagara Falls stopped flowing.