A small area of rapidly descending air beneath a thunderstorm can cause damaging winds in excess of 100 mph. The action of rising and descending air within a thunderstorm separates positive and negative charges. Water and ice particles also affect the distribution of electrical charge. Lightning results from the buildup and discharge of electrical energy between positively and negatively charged areas. The average flash could light a 100-watt light bulb for more than 3 months.
Most lightning occurs within the cloud or between the cloud and ground.
The rapid heating of air in the lightning channel causes a shock wave that results in thunder. A cloud to ground lightning strike begins as an invisible channel of electrically charged air moving from the cloud toward the ground. When a channel nears an object on the ground, a powerful surge of electricity from the ground moves upward to the cloud and produces the visible lightning strike. Your chances of being struck by lightning are one in 600,000 but can be reduced by following safety rules. Most lightning deaths and injuries occur when people are caught outdoors.