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. Thunderstorms can bring heavy rains (which can cause flash flooding), strong winds, hail, lightning, and tornadoes. Severe thunderstorms can cause extensive damage to homes and property.
Lightning is a major threat during a thunderstorm. Lightning is an electrical discharge that results from the buildup of positive and negative charges within a thunderstorm. When the buildup becomes strong enough, lightning appears as a "bolt." This flash of light usually occurs within the clouds or between the clouds and the ground. A bolt of lightning reaches a temperature approaching 50,000 degrees Fahrenheit in a split second. The rapid heating and cooling of air near the lightning causes thunder.
In the United States, between 75 to 100 Americans are hit and killed each year by lightning. Morbidity is reduced if, when caught outdoors, individuals avoid items which act as natural lightning rods, such as tall isolated trees in an open area or the top of a hill, and metal objects such as wire fences, golf clubs, and metal tools. It is a myth that lightning never strikes twice in the same place. In fact, lightning may strike several times in the same place in the course of one discharge.
While thunderstorms and lightning can be found throughout the United States, they are most likely to occur in the central and southern states. The state with the highest number of thunderstorm days is Florida.
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American Public Health Association © 2005 American Public Health Association
Cite this: Types of Disasters and Their Consequences - Medscape - Sep 20, 2005.