The typical thunderstorm is 15 miles in diameter and lasts an average of 30 minutes. Nearly 1,800 thunderstorms are occurring at any moment around the world. That's 16 million a year. Of the estimated 100,000 thunderstorms that occur each year in the United States, only 10 percent are classified as severe. Every thunderstorm produces lightning, which kills more people each year than tornadoes.
Heavy rain can lead to flooding.
Strong winds and tornadoes are also dangers associated with some thunderstorms. Along the Gulf Coast, most thunderstorms occur during the afternoon. Lightning causes an average of 93 deaths and 300 injuries annually and causes several hundred million dollars in damage. Florida leads the nation in the number of lightning death and injuries. Most flash flood deaths occur when people become trapped in their automobiles.