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About Niagara Falls
Located between the twin cities of Niagara Falls, Ontario, and Niagara Falls, New York, the Niagara Falls system of waterfalls was formed over 10,000 years ago from the Wisconsin Glacial Episode. Up until that time, ice covered much of North America, but when the glaciers began to move and recede, the Falls were formed.
Technically, there are 3 separate waterfalls that make up the Niagara Falls system. The American & Bridal Veil Falls are part of the U.S. System, while the Horseshoe Falls is on the Canadian side.
The waters of Lake Erie feed the Niagara River, which flows directly to Niagara Falls. During the winter, chunks of ice form in the lake. They are pushed downstream and over the Falls, blocking the flow of water in the Niagara River, which reduces the water levels in the Falls themselves.
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Did the Falls freeze?
Over the centuries, there have been multiple times when ice from further up in the stream created a lower flow of water than normal during the winter, resulting in instances some people have referred to as a Niagara Falls great freeze.
The American Falls has a lower water flow than the Horseshoe Falls, which causes less water to flow over the rock face of the Falls and allows for that water to freeze quickly. Since records have been kept, the American Falls has frozen a total of six times in 1883, 1896, 1904, 1909, 1936 and 1947, with the longest occurring in February of 1936.
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How Ice Bridges contribute to freezing
Ice bridges also form at the base of the Falls in the winter months.
The water flows very quickly through the Niagara River, but the ice chunks that go over the Falls collect and freeze to the rocks surrounding the base. Water continues to build on the ice that is there, resulting in an ice sheet or ice bridge that can accumulate anywhere from 40 to 80 feet thick. Air still manages to accumulate beneath the ice, which allows the water to continue to flow beneath the ice. That means the river does not completely freeze over.
In the early years of tourists visiting Niagara Falls, people were actually allowed to walk out onto the ice bridges that had formed at the base of the Falls. But in 1912, the ice bridge broke apart and 3 people who became stranded on chunks of the ice flow were swept down river, into the Whirlpool Rapids and drowned.
In 1938, a massive chunk of ice was swept down river from Lake Erie. It caused a chain raction of mouting ice and rising water levels which damaged the generators of the power station, and also crushed the docks of the Maid of the Mist and did so much damage to the Falls View Steel Arch Bridge that it collapsed a few days later.
In the 1960’s, an ice boom was placed at the mouth of the Niagara River to keep the ice from Lake Erie from flowing into the lower gorge of the river so an ice bridge will not form, yet it still allows water to continue flowing downstream.
Today, the New York Power Authority & Ontario Power Generation share the responsibility of tending to the 8,800-foot-long ice boom, which consists of steel pontoons that are linked together and anchored to the river’s bottom at Lake Erie's outlet to the Niagara River.
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The Niagara Falls system is an awe-inspiring natural wonder that continues to thrill visitors every year. By respecting the power of the Falls, we will be able to continue to safely enjoy their beauty for years to come.
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Niagara Parks.com. Niagara Parks Media Center
Van-de-Velde, Zoe, on Bright Hub Multimedia: How to Photograph Waterfalls and Rivers - Digital Photography Tips