Close to the lightning strike the thunder may be heard as a short loud crack. One can work out how far away the lightning strike was by counting the time taken for the thunder to arrive. A 5 seconds difference is roughly equal to a distance of 1 mile. In warmer regions of the world thunderstorms can be particularly violent because they contain so much energy , made available from the strong surface heating by the Sun. Such thunderstorms may also be accompanied by tornadoes , rapidly spinning columns or spouts of air.
Tornadoes are particularly common in the central United States.
It is estimated at any given moment nearly 2,000 thunderstorms are in progress over the Earth's surface, and lightning strikes the Earth 100 times each second. There are about 45,000 thunderstorms daily and 16 million annually around the world. Thunderstorm from space Weather Print Topic Websites US Weather Service US Severe Storms Lab.