Here is more about the basic science in lightning . A lightning flash may be two or three hundred feet long, sometimes much longer. Though the lightning flash looks very wide, most of what you see is just glowing air. The actual flash may only be as wide as a pencil. Though a lightning strike will only last a few milliseconds, it is extremely hot.
Thunder is nature's best warning Thunder is the sound that lightning makes.
If you can hear it, that normally means there is lightning within 10 miles. If that is less than 30 seconds chances are very good that lightning is close enough to create an immediate danger to you. One dangerous myth is that if you can't hear thunder there is no lightning nearby. The Top Ten myths about lightning give a good idea give a good idea of how wrong most people are about their safety during a lightning storm. They offer important guidance on good ways to protect yourself.