April 18, 2004
The above photo showing cloud-to-ground lightning was taken during a vigorous thunderstorm in Adelaide, Australia during July (winter in the Southern Hemisphere). A lightning flash is composed of a series of strokes (an average of about four). While the length and duration of each stroke varies, an average of approximately 30 microseconds is typical. The average peak power per stroke is about 1,012 watts, and temperatures can exceed 50,000 F. At least this particular storm provided some entertainment to the weeks of constantly gray skies and rainy conditions that preceded it.