Although only a small fraction of all thunderstorms develop into severe storms, the ones that do can cause major damage. One of the destructive features of severe thunderstorms, hail, annually causes several hundred million dollars in crop damages. Downbursts, intense wind produced during a thunderstorm, can produce surface wind speeds faster than 80mph. This can damage buildings, or keep planes from taking off and landing. If the storm stays in one place for days at a time, flash flooding could occur. Because urbanization has expanded into flood plains, flash flooding is ranked as the number one storm related killer. Intense lightning is the number one cause of forest fires in the U.S. Tornadoes, probably most associated with severe thunderstorms, can wreak havoc almost anywhere. Just recently, Nashville, TN's east side was devastated by tornadoes.
