Weather for Kids

Subject: Lightning

What causes lightning? Do you know any lightning safety rules? First, lets talk about how lightning forms in a cloud. A thunderstorm cloud, or cumulonimbus, consists of rapidly moving air, called updrafts and downdrafts, containing both ice crystals and water droplets. Friction between the moisture and air particles creates positive and negative electrical charges in a cloud. Typically, negatively charged particles, mainly rain drops, gather at the base of a thunderstorm, while positive charges, mainly snowflakes congregate near the top of a thunderstorm. The surface of the Earth also generates an electrical charge, usually opposite that of the lower part of the thunderstorm. When the electricity within the cloud, or between the cloud base and the ground becomes very strong, a connection is made and a discharge is released. The result is a bright flash called the lightning bolt.

One thunderstorm can generated hundreds of lightning bolts during its lifetime. Lightning strikes are unpredictable and can bolt between two different clouds, from the cloud to the ground, and even from the cloud to clear air. Lightning bolts can strike the ground directly under the cloud, whether it's raining or not, or strike well over ten miles away from the center of the thunderstorm. Lightning is very dangerous and can seriously injure and kill people who are struck.

Here a few lightning safety tips. If a thunderstorm is approaching, you should go indoors. If a safe shelter is not possible and you are caught outside with lightning all around, crouch low to the ground so that you are not the tallest object. You should avoid standing near tall trees or other tall objects during a thunderstorm. Lightning can travel through electrical wires and telephone lines that connect to your house, so it's not very wise to be on the phone during a thunderstorm.

Do you know the 30-30 Rule? If you can hear thunder within 30 seconds following the first lightning flash, or flash-to-bang time, you are no longer safe and should move to an enclosed shelter. Then, you should stay indoors until 30 minutes following the last thunder heard from the storm.