MIKKEL JUUL JENSEN / SCIENCE PHOTO LIBRARY MIKKEL JUUL JENSEN / SCIENCE PHOTO LIBRARY
Hurricane formation. Diagram showing the formation of a hurricane (tropical cyclone). At left, clouds form over warm tropical waters, powered by the energy in sunlight causing evaporation of seawater. Rapid formation of clouds leads to updrafts and air moving inwards. The second diagram shows the winds and clouds beginning to rotate. This is caused by the Earth's rotation. As the energy within the storm builds, wind speeds increase with a hurricane declared when the winds reach 120 kilometres per hour. At right, structures seen in a mature hurricane include the eye, the eye wall, bands of rain, a spiralling vortex of warm air in the eye, and an outflow of cold air (blue arrows) at the outer edges of the hurricane.
Model release not required. Property release not required.