A tidal bore, also known as a surge, is a massive and often single wave caused by the constriction of an incoming spring tide, as it gets funneled up a narrow and shallow river. Bores are relatively rare and usually only take place in regions with a tidal range of more than 20 feet, i.e., in areas where there are huge water level differences between low and high tide. As the set of waves funnel into a narrow river, bay or lake, they accumulate energy and accelerate against the natural direction of the stream.

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What is a tidal bore?

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