Tornadoes formed at sea, seen from Toulon, France, 28th February 1881.
© Science Museum / Science & Society Picture Library
'Trombes Formees en Mer en Vue de Toulon le 28 Fevrier 1881.' Illustration by A Tissandier after a drawing by M F Zurcher, taken from 'La Nature' (Paris, 1881) edited by Gaston Tissandier. A waterspout is a meteorological phenomenon similar to a tornado, that forms over water. It is a rapidly rotating vortex of intense low pressure, extending from the base of a cloud to the surface of the water. The spout does not actually consist of water sucked up from the surface, but is in fact water vapour condensing in the core of the vortex.