Lightning is caused by the attraction between positive and negative charges in the atmosphere, resulting in the buildup and discharge of electrical energy. A lightning flash can happen in half a second. In that instant, the lightning flash superheats the surrounding air to a temperature five times hotter than that on the surface of the sun, or 50,000 degrees Fahrenheit. Nearby air expands and vibrates, forming sound that we hear as thunder.

Here's an interesting note: Sound travels more slowly than light, so it seems that thunder actually occurs later.

Lightning is one of the most underrated severe weather hazards, yet it ranks as the second-leading weather killer in the United States. More deadly than hurricanes or tornadoes, lightning strikes in America each year kill an average of 73 people and injure 300 others, according to the National Weather Service.

More people are killed by lightning than by any other kind of storm, including hurricanes and tornadoes. There are thousands of lightning strikes every day. Scientists think that lightning hits somewhere on the earth about 100 times every second. While it is difficult to obtain accurate statistics on lightning injuries and fatalities, it is estimated that each year, in the United States alone, lightning is responsible for the deaths of a hundred people, injuries to several hundred more, and millions of dollars in property damage. Eighty - five percent of lightning victims are children and young men between the ages of 10 and 35 engaged in recreation or work.

Twenty percent of lightning strike victims die and 70% of survivors suffer serious long-term after-effects. Many case histories show heart damage, inflated lungs and brain damage. Loss of consciousness, amnesia, paralysis and burns are reported by many who have survived. Lightning strikes also result in deaths and injuries to livestock and other animals, thousands of forest and brush fires, as well as millions of dollars in damage to buildings, communications systems, power lines, and electrical systems.