“Heat lightning” flashes too far away for you to hear the thunder. Usually you can’t hear thunder when the lightning is more than about 10 miles away. When the lightning is inside clouds, the clouds spread out the light of the flash so instead of seeing a streak of lighting, you might see a wide flash, which is why it’s often called “sheet” lightning.” Jack Williams, USATODAY.com weather editor

Lightning can strike as far as 10 miles from a thunderstorm which is about the distance you can hear thunder.

You can learn a lot more by going to our Resources: Lightning science and safety page at http://www.usatoday.com/weather/resources/basics/wlightning.htm

A golf cart will not protect you. The only safe vehicle is one that is enclosed with a metal top. An enclosed metal body allows the lightning to be directed through the metal body around you, and then into the ground.