Waterspout
Waterspout, a whirlwind over water. Within the waterspout is an area of rising air currents and relatively low pressure. The whirlwind usually forms a funnel-shaped or ropelike cloud. The cloud consists of water vapor that has condensed because of the low pressure in the waterspout. The waterspout sucks up some water from the surface, but almost all the moisture in the waterspout comes from the air.
Some waterspouts are tornadoes spawned by severe thunderstorms. Most waterspouts, however, are much less violent than a tornado. These waterspouts typically occur during fair weather over warm waters in the tropics or subtropics when a strong current of warm air rises from near the surface of the water. Air rushes in to replace the rising air, causing the rising air to spin.