There is also ball lightning. It usually is seen shortly before or after, or during, a thunderstorm. Its duration varies from a few seconds to a few minutes.
The lifetime of ball lightning tends to increase with size and decrease with brightness. Balls that appear distinctly orange and blue seem to last longer than average.
Ball lightning usually moves parallel to the earth, but it takes vertical jumps. Sometimes it descends from the clouds, other times it suddenly materializes either indoors or outdoors or enters a room through a closed or open window, through thin nonmetallic walls or through the chimney.
The term refers to reports of luminous, usually spherical objects which vary from pea-sized to several meters in diameter. It is usually associated with thunderstorms, but lasts considerably longer than the split-second flash of a lightning bolt. Many of the early reports say that the ball eventually explodes, sometimes with fatal consequences, leaving behind the odor of sulfur
Here is more,...
http://physicsworld....ls-of-lightning http://en.wikipedia..../Ball_lightning
Edited by Hazzard, 18 June 2012 - 10:53 PM.