Britta's Weather Lab: How does lightning work?


HOUSTON – Lightning is very powerful, but also fascinating to learn about. Here's how lightning works:

Clouds are made out of tiny droplets of water. In thunderstorms, these tiny droplets of water soar high into the air, sometimes as high as air planes fly! Temperatures are very cold that high in the atmosphere and the tiny droplets of water freeze into ice. These tiny bits of ice are moved around by strong winds inside the storm.

As more tiny bits of ice collide and charges build, the positive charges stay at the top of the storm while the negative charges fall to the bottom. Negative and positive charges are attracted to each other.

Eventually charges build up inside the storm and they begin to pull toward each other. This can happen inside the cloud which would produce lightning inside the cloud, but it also occurs between the storm and the ground. Negative charges in the cloud are attracted to positive charges on the ground and start to move toward the ground. At the same time, positive charges on the ground are attracted to the negative charges in the storm and start to move upward toward the storm.

Eventually the negative charges from the cloud -- step leaders -- meet the positive charges moving up from the ground -- streamers. When they connect, lightning strikes!

I hope this helps explain lightning. Check out the Britta's Weather Lab page for more cool weather facts!