The warm, humid conditions of the spring and summer seasons greatly favor the development of thunderstorms, though thunderstorms can occur at any time of year. Thunderstorms may occur singly, in clusters or in lines and usually only produce heavy rain for a brief period of time ranging from 30 minutes to an hour. However, the most severe thunderstorms can affect one location for an extended period of time. At any given time, nearly 1,800 thunderstorms simultaneously are occurring on Earth (American Red Cross, 2012), and can develop into conditions such as tornadoes and damaging hail. Lightning strikes can be fatal, and there also is a variety of permanent injuries employees can develop as a result of a lightning strike. These injuries can include – but are not limited to – muscle spasms, chronic pain, sleep disorders, memory loss and fatigue (National Weather Service [NWS], 2012). According to NWS, lightning kills more than 70 people and injures at least 300 others each year in the United States. In 2012, there have been at least five reported fatalities attributed to lightning strikes in the United States.

Due to the immense amounts of rainfall that can occur during thunderstorms, flash flooding also accounts for roughly 140 fatalities each year in the United States, according to the Federal Emergency Management Agency (FEMA). The deaths that occur during flash flooding are greater than any other hazard associated with thunderstorms. And the destruction due to thunderstorms does not stop there. When severe high winds are present, homes and automobiles also can be damaged. High winds can knock down trees and utility poles, which can cause extensive power outages and account for a handful of deaths each year.