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.
Most lightning occurs within the cloud or between the cloud and ground.
When one 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. Lightning occurs with ALL thunderstorms. The air near a lightning strike is heated to 50,000 degrees Fahrenheit hotter than the surface of the sun. The rapid heating and cooling of air near the lightning channel causes a shock wave that results in thunder. In the United States, lightning kills more people each year than tornadoes.