Thunderstorms are the most common form of violent weather on Earth. They form in large cumulonimbus clouds. These are the biggest clouds of all, and produce heavy showers, hail, and thunderstorms. A thunderstorm happens when a cloud's moisture water droplets and rising warm air combine. Some thunderstorms stir up winds of over 160 kph 100mph. Thunderstorms may cause lightning as well, which are bright flashes of light in the sky.

Thunderstorm