vesipylvään

Vesipylvään, also known as a waterspout, is a meteorological phenomenon characterized by a rotating column of air that forms a condensation funnel extending from the base of a cloud to the surface of a body of water. These are essentially tornadoes that occur over water. Vesipylvään can vary in intensity and size, ranging from small, weak whirls to large, powerful storms capable of causing significant damage.

The formation of a vesipylvään typically begins with unstable atmospheric conditions, often associated with thunderstorms. Warm, moist air near the water surface rises rapidly, creating updrafts. If there is sufficient wind shear, or a change in wind speed and direction with height, the rising air can begin to rotate. This rotation can tighten and intensify as it stretches vertically, forming the characteristic funnel shape. The funnel is made visible by condensed water vapor and debris picked up from the water's surface.

While most vesipylvään are relatively harmless and dissipate quickly, some can be quite destructive. They can capsize boats, damage coastal structures, and pose a serious threat to anyone caught in their path. The intensity of a vesipylvään is often measured using the Enhanced Fujita Scale, similar to tornadoes, though generally they are less powerful than land-based tornadoes. Observing a vesipylvään usually requires caution, and boats are advised to steer clear of them.