When a disturbance over a warm and tropical ocean make a cyclonic circulation around a point of low pressure, it has reached the next development stage, which is known as a tropical depression. When the wind speeds around the low-pressure center grow to exceed 65 kilometers per hour, the new system is then called a tropical storm. If the pressure of the air drops even more and the winds around the center reach at least 120 kilometers per hour, the storm will officially be classified as a hurricane. The centers of hurricanes, known as the eye, are calm and cloudless. Hurricanes last until it can no longer produce enough energy to keep going, usually when the hurricane moves over land.

A tornado is a violent, whirling column of air in contact with the ground that forms when wind direction and speed suddenly change with height, is often associated with a...