Some weak tornadoes, known as landspouts, have been shown to develop in a similar manner. They normally develop in moisture-laden environments as their parent clouds are in the process of development, and it is theorized they spin as they move up the surface boundary from the horizontal shear near the surface, and then stretch upwards to the cloud once the low-level shear vortex aligns with a developing cumulus cloud or thunderstorm. While some waterspouts are strong and tornadic in nature, most are much weaker and caused by different atmospheric dynamics. The cloud from which they develop can be as innocuous as a moderate cumulus, or as great as a supercell. Waterspouts exist on a microscale, where their environment is less than two kilometers in width. Waterspout in the Tasman Sea, 29 January 2009 Waterspouts are also frequently observed off the east coast of Australia, with several being described by Joseph Banks during the voyage of the Endeavour in 1770. In the Northern Hemisphere, September has been pinpointed as the prime month of formation. Approximately 160 waterspouts are currently reported per year across Europe, with the Netherlands reporting the most at 60, followed by Spain and Italy at 25, and the United Kingdom at 15.
coast, especially off southern Florida and the Keys, and can happen over seas, bays, and lakes worldwide. Waterspouts are more frequent within 100 km (60 mi) from the coast than farther out at sea. They are fairly common on the Great Lakes during late summer and early fall, with a record 66+ waterspouts reported over just a seven-day period in 2003. They are not restricted to saltwater many have been reported on lakes and rivers including the Great Lakes and the St. Though the majority of waterspouts occur in the tropics, they can seasonally appear in temperate areas throughout the world, and are common across the western coast of Europe as well as the British Isles and several areas of the Mediterranean and Baltic Sea. Although rare, waterspouts have been observed in connection with lake-effect snow precipitation bands.Ĭharacteristics Climatology Some are also found on the East Coast of the United States, and the coast of California. While waterspouts form mostly in tropical and subtropical areas, they are also reported in Europe, Western Asia (the Middle East), Australia, New Zealand, the Great Lakes, Antarctica, and on rare occasions, the Great Salt Lake. Īlthough typically weaker than their land counterparts, stronger versions-spawned by mesocyclones-do occasionally occur. Most waterspouts do not suck up water they are small, weak rotating columns of air over water. In the common form, a waterspout is a non- supercell tornado over water having a five-part life cycle: formation of a dark spot on the water surface spiral pattern on the water surface formation of a spray ring development of a visible condensation funnel and ultimately, decay. Some are connected to a cumulus congestus cloud, some to a cumuliform cloud and some to a cumulonimbus cloud. A waterspout is an intense columnar vortex (usually appearing as a funnel-shaped cloud) that occurs over a body of water.
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