On average, the United States gets 100,000 thunderstorms each year. Approximately 1,000 tornadoes develop from these storms. Straight-line winds exceeding 100 mph are responsible for most thunderstorm damage. The power of lightning's electrical charge and intense heat can electrocute on contact, split trees, ignite fires and cause electrical failures. A thunderstorm is formed from a combination of moisture, rapidly rising warm air and a force capable of lifting air such as a warm and cold front, a sea breeze or a mountain.
All thunderstorms contain lightning.
Thunderstorms may occur singly, in clusters, or in lines. Thus, it is possible for several thunderstorms to affect one location in the course of a few hours. Some of the most severe weather occurs when a single thunderstorm affects one location for an extended time. Lightning is an electrical discharge that results from the buildup of positive and negative charges within a thunderstorm. This flash of light usually occurs within the clouds or between the clouds and the ground.