Thunderstorms always start in clouds. When a cloud grows very fast it becomes a thundercloud. Inside a thundercloud there are many charged particles, and they want out! But how did they get in there? A cloud consists of many small drops of water and ice. The air in a thundercloud rises very quickly, making the water and ice rub against each other. That is how the charged particles are formed. These charged particles want to jump over to another cloud or to the ground. That’s what causes lightning. Lightning is extremely hot. The temperature of the air rises in a very short time, causing the air to expand and making a loud bang. If you can count to three, the thunderstorm is about a kilometer away. Every three seconds is a kilometer. When you can count to ten, the thunderstorm is approximately three kilometers away: a safe distance. But if there are less than ten seconds between you and the thunderstorm, you had better get inside!