Reply #3: Lightning Myth: Lightning doesn't strike the same place twice. [View All]

[RobertSeattle]

Was just curious if I could find something about that on the internet.

http://www.weatherimagery.com/myths_lightning.php

Lightning does and will strike the same exact place more than once. If you don't believe me, just ask some of the employees at Cape Canaveral in Florida. The shuttle launch pad gets hit time and time again, sometimes more than once in the same storm. Or, how about the Empire State Building in New York city which gets struck by lightning about 500 times each year! The one thing lightning loves is very tall objects and it doesn't care how many times it strikes. The truth of it is, lightning is simply trying to balance a charge separation; positive and negative. Very tall objects, such as skyscrapers and radio towers are more likely to be struck because those objects provide a bigger bridge between the charge separation (the ground and the oppositely charge cloud above). The opposite charge will rush upwards along the structure more easily than through the air and as a result the gap between the two charges is lessened increasing the chance of a strike.

Now, objects that are taller than their surroundings aren't always the lightning's first choice. Otherwise every tree, telephone pole, and house on the open prairie would have the unfortunate pleasure of being struck. The fact is, objects closer to the ground play a much smaller role in determining what is going to be struck because they don't provide as large a bridge between the charges. Lightning doesn't know what it's going to strike until the last 50 to 100 feet. That is to say, lightning doesn't know at 50,000 feet that its going to strike your neighbors satellite dish. Lightning zig-zags down to the ground by forming "step-leaders", re-evaluating at each step where it's going next. Sometimes left, sometimes right, sometimes down, sometimes up. Once the step-leader approaches a grounded object, a "streamer" composed of the opposite charge shoots upwards. One can shoot up from a telephone pole, a tree, a car or all three simultaneously. Whichever one connects with the descending step leader first will bridge the charge separation gap and trigger a mass rush of electricity creating a lightning bolt. But the taller object might not be the closest one and it might not throw up as tall a streamer. The tallest object may be just a 100 feet further away than a shorter one and the shorter one will get hit because its streamer made contact with the step leader first.