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.
The average flash of lightning could turn on a 100-watt light bulb for more than 3 months. The rapid heating and cooling of air near the lightning channel causes a shock wave that results in thunder. Your chances of being struck by lightning are estimated to be 1 in 600,000 but those chances can be reduced by following safety rules. Most lightning deaths and injuries occur when people are caught outdoors, and most happen in the summer. Many fires in the western United States and Alaska are started by lightning.