Thunderstorms are small, intense weather systems that make strong winds, heavy rain, lightning, and thunder. Thunderstorms can happen anywhere with two conditions: the air near the Earth's surface must be warm and moist, and the atmosphere must be unstable. 100 lightning bolts hit the earth every second, and at any one moment, about 1,800 thunderstorms happen around the earth.
This energy moves to the air and makes it to spread quickly and send out sound waves. Thunder is the sound that comes from the rapid spread of air along the lightning strike. Thunder is slower than lightning, because light is faster than sound.
About 10% of thunderstorms are thought severe. Severe thunderstorms make things like high winds, hail, flash floods, and tornadoes. Hailstorms damage crops, damage the metal on cars, and break windows. Sudden flash floods that happen because of heavy rains is the biggest reason for weather-related deaths.
Thunderstorms do not do only damage, however: they can be a great help to man and all living creatures. We get lots of water for many continents during the summer. Plants receive lots of life-giving rain when they need it. Without the thunderstorms, many continents would become dry. Fish would die, crops would fail, and animals would perish.
Thunderstorms are also our natural air conditioners. Hot air at the surface rises up into the high atmosphere where it is put out into space. Clouds give us shades, and rain can cool down a hot day. Without thunderstorms, the earth would be as much as 20 F (11 C) warmer. In the summer, dust, haze, and other pollutants come together in the lower atmosphere. When the air rises, either in cumulus clouds or in thunderstorms, spreads the pollution higher up into the atmosphere. Rain from thunderstorms washes away many of these pollutants out of the air.