Spray ring: A dense swirling ring of sea spray, called a cascade, appears around the dark spot with what appears to be an eye similar to that seen in hurricanes.Spiral pattern: A pattern of light- and dark-colored surface bands spirals out from the dark spot that developed on the water surface.Dark spot: A prominent circular, light-colored disk appears on the surface of the water, surrounded by a larger dark area of indeterminate shape and with diffused edges.Golden distinguishes five stages of waterspout formation: "They tend to last from about 2 to 20 minutes and move along at speeds of 10 to 15 knots (about 12 to 17 mph)." "Waterspout formation typically occurs when cold air moves across the Great Lakes and results in large temperature differences between the warm water and the overriding cold air," the NWS said. This type of waterspout is generally small, brief and less dangerous than a tornadic waterspout.Īccording to the National Weather Service, waterspouts occur most frequently in the Great Lakes from August through October, when water temperatures are near their warmest levels of the year. Fair-weather waterspouts form at the surface of the water and rise upward in association with warm water and high humidity in the lower portion of the atmosphere. The more common type, a fair-weather waterspout, is one that develops over open water.
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