A video has emerged from the United States of a massive waterspout which formed off the coast of Florida.

The impressive clip, which was filmed in Dunedin on August 18, shows the giant twister swirling close to the town.

"I spotted the waterspout from miles away because it was so huge and ominous," the filmer wrote online.

"When I arrived at the location it struck hardest, police were everywhere, trees down, firetrucks, building damage and a few unfortunate injured people including one child," the filmer added.