And most lightning researchers are still quick to suggest this possibility. Mazur's mathematical analysis, however, suggests they would be 95 percent wrong. Our unfortunate ignorance about how even a single cloud produces a zap bodes ill for a definitive answer. As a field or body of water heats up during the day, a column of warm air rises over it. As the air at the top of the column reaches cold air, it cools, and the moisture it holds condenses.
Strong convection carries moisture higher, where it turns to ice crystals.
A tall, fluffy storm cloud is born, inside of which air and moisture particles circulate. The lower part of the cloud now carries a strong negative charge. Just as one magnet will repel another, so this cloud drives away electrons on the ground far below, creating a shadow of faint positive charge. When the storm cell is adequately charged a spark jumps to life. How this spark propagates itself is unknown.