MYTH: Small metal objects attract lightning, and I'm safer outside without any metal nearby. (OR)
MYTH: Wearing jewelry, wearing shoes with metal cleats or carrying metal objects such as tripods, golf clubs and umbrellas will attract lightning and make me more susceptible to a strike.
TRUTH: For all intents and purposes, nothing 'attracts' lightning. Lightning occurs on too large of a scale to be influenced by small objects on the ground, including metal objects. The location of the thunderstorm overhead alone determines where lightning will hit the ground. A lightning bolt that is several miles long, generated by a cloud that is more than 6 to 10 miles high, is not going to be influenced by your jewelry, or even your house. Visualize your 30-foot high house, your 3-foot umbrella, or your 1/2 inch earring next to a thundercloud 55,000 feet high and 15 miles in diameter, and you can begin to see the relative insignificance of objects on the ground when it comes to a lightning discharge. The graphic below is an approximation of what Chicago's Sears Tower looks like when superimposed next to a thunderstorm. Visualize your umbrella or earrings scaled to size on this picture - they wouldn't even be visible.
The more lightning is studied and photographed, the more it is found to defy these age-old myths. It strikes the ground next to buildings, trees and metal poles (see photo below). It hits in valleys at the base of huge mountains. Sometimes it connects to the sides, not the top, of skycrapers. Even at research labs where rocket-triggered lightning is used to test lightning rods, many times the lightning misses the test rods altogether and strikes bare, metal-less ground nearby!
Lightning in Pittsburgh, Pennsylvania
The descending stepped leader of a lightning bolt doesn't 'decide what to strike' until it is very close to the ground. The only way a small conductive object like an umbrella would 'attract' a lightning channel is if the lightning already was about to strike less than three to five feet away. And your hair beret or necklace will only draw a lightning channel to it if it's less than a couple inches away - in which case the lightning would already be striking you to begin with!
The danger of this myth is that it fosters the assumption that it is safer to be outdoors if you just isolate yourself from metal objects. The truth is that it's just dangerous to be outside during a storm, period- with or without metal nearby.
You could compare this myth to the one that suggests that you can jump up and down on the San Andreas Fault in California and trigger an earthquake. Since earthquakes are caused by the buildup and release of tremendous, large-scale forces (from movement of huge tectonic plates that make up the earth's crust), a person jumping up and down on the fault, or even a bomb exploding over the fault, are tiny specks compared to the enormous forces working inside the earth to create earthquakes. On the same token, the forces inside a thunderstorm that create lightning are much too large to be influenced by small metal objects on the ground that are tiny specks in comparison. When a cloud-to-ground lightning channel is forming, it is going to strike the ground where the opposing charges are greatest, directly underneath the storm's most electrically active region. If you are standing at that exact location, you will be hit, even if there's no metal within miles! Conversely, if you are farther than 500 feet from that location, you could wave your golf club or umbrella high in the air, but you won't draw the lightning away, even slightly, from striking where it's going to strike.
So is it safe to be outside and wave an umbrella or golf club in the air during a storm? Absolutely not! Not because of the umbrella or golf club, but simply because you're outside where the lightning is occurring!
The one valid claim against wearing jewelry is that in the event that you were hit directly, the lightning may flow through any metal on your person, superheating (or even vaporizing) it and causing severe burns. But frankly, in that case, burns will be the least of your problems.
It has been found that the 'degree of influence' of metal objects on lightning is proportional to the size of the object. Photographic and laboratory evidence suggests that a conductive object will only attract a lightning channel at a distance at or less than the object's longest vertically-oriented dimension. That is, a three-foot high umbrella will not attract or influence a lightning channel that strikes more than three feet away (see illustration below). A metal earring will only attract a lightning bolt that is less than one-half of an inch away! A house or building may attract a lightning bolt that comes down at or less than a distance equal to its height. In other words, for most objects on the ground, a lightning strike must already be occuring at extremely close range for any attraction effects to come into play. This makes any relevance to safety a moot point, as lightning striking within a few feet of a person standing outside is usually just as lethal as a direct hit.
Small metal objects will not attract a lightning channel that is further away than a distance equal to the object's length. Lightning would have to strike within three feet of this umbrella before it could be 'attracted' to the umbrella.
A tall television broadcast tower or a mega-skyscraper introduces a huge leap in size, and the resultant 'degree of influence', from an umbrella, earring or house. Not only is their immense size incomparable to small metal objects on the ground, these structures significantly reduce the insulating air gap bewteen a thunderstorm cloud and ground - something a house, golf club or umbrella fails to do. Using the degree of influence concept, we can conclude that a broadcast tower that is 1,500 feet high is likely to draw a lightning strike that is occuring within a 1,500-foot radius of its antenna tip. Photographic evidence of lightning strokes to these structures have reinforced this concept.