It's late in the afternoon. The white puffy clouds that have been growing all day are replaced by a gray sky. It starts to rain. Welcome to a thunderstorm.
Thunderstorms are one of the most thrilling and dangerous of weather phenomena.
Over 40,000 thunderstorms occur throughout the world each day. Thunderstorms can cause a lot of damage. Tornadoes can uproot trees and demolish buildings. Hail can damage cars and crops. Heavy rain can create flash floods.