|WHAT CAUSES LIGHTNING AND THUNDER?
METEOROLOGIST JEFF HABY
Lightning is a flash of light created by electric discharge. It is extremely bright for a brief
moment in time even at great distances. You have probably seen static electricity where you
see a small spark. Lightning is similar except of course on a much bigger scale. Lightning
requires a big vertically developing cloud complex. A cloud that produces lightning will tend
to also have rain falling out of it. The precipitation process within a cloud is a reason
lightning occurs. As ice and water develop in clouds there is an electrical buildup. The electrical
buildup on each ice and water drop is very small but the huge number of ice crystals and water
drops creates a large electrical difference between different portions of the cloud. Lightning
occurs to balance the electrical build in the clouds or between the clouds and the ground.
Thunder is created by a rapid expansion of air. Think of a balloon popping. There is a sudden
release of noise due to the rapid expansion of air. When lightning moves through the air it
increases the temperature of the air dramatically in a very short period of time. The air
then cools rapidly. This rapid expansion and contraction of the air gives off the sound
waves that is heard from the lightning.
Lightning is very dangerous. Make sure to stay inside when there is lightning.