1911 Encyclopædia Britannica/Waterspout
WATERSPOUT, a local vorticular storm occurring over a water-surface, and in origin and form similar to a tornado (q.v.) over the land. A whirling, funnel-shaped cloud, first observed as a pendant fr«m the mass of storm-cloud above, seems to grow downwards, tapering, towards the water-surface, which is violently agitated, and finally (when the spout is fully developed) appears to be drawn up to meet the cloud from above. This appearance is deceptive, as the bulk of the water carried along by the whirling spout is condensed from the atmosphere, and, even when the spout is formed over a salt-water surface, is found to be fresh. Waterspouts occur most frequently over the warm seas of the tropics, but they are not confined to the warmer tropical seasons, or even to low latitudes.