What Causes Lightning: Distinguishing Facts from Myths

The properties and effects that characterize a lightning strike are truly remarkable. Lightning begins as a high-intensity electric impulse that initially grows in a gaseous environment while forming in the atmosphere and then evolves into a solid, more or less conductive medium when it strikes the ground. However, the fireworks that take place during this celestial trip from heaven to earth can be simultaneously wonderous and devastating. The visual effects of the lightning flash followed by the shockwave of thunder and the sheer thermal dynamics of the heat generated by the event also create residual electrodynamic and electrochemical side-effects that can disrupt power, create electrical surges in office and industrial devices and interrupt network communications.

A lightning strike is perhaps one of the most feared and yet wonderous natural occurrences. When you figure that a person’s odds of being struck by a lightning bolt are a minuscule one in 12,000, yet astraphobia is the third most common phobia in America, behind acrophobia (fear of heights) and zoophobia (fear of animals), it proves most people respect its savage potential. However, climate scientists are wary that with the earths rapid weather changes, the chances of being a lightning-strike victim could increase to one in 8,000 by the year 2100.

What is Lightning?

So, what causes lightning and the residual effect we call thunder? Lightning is created when a positive and negative electrical charge grow and expand large enough to be seen in the sky. Thunder is the sound lightning makes when the pressure and temperature around that charge suddenly increase, expanding the air and creating a loud boom.

The definitive cause of lightning is still up for debate among scientists who know it is related to the interactions between positive and negatively charged ions within clouds, something similar to walking across a carpet and then touching a doorknob only to get shocked because of the discharge of static electricity. Movement across the floor generates an unstable static electric charge. A similar reaction occurs within a lightning cloud but on an exponential scale.

Myths About Lightning

People have been fascinated by lightning since the first human, with myths and legends rooted in the power and majesty of the arching bright light sprinkled throughout world literature and oral histories. But failing to understand some of the myths can lead to serious issues when humans and lightning collide.

Take the famous story in which Benjamin Franklin supposedly flew a kite into a thunderstorm and collected lightning in a jar. This could be true in a magical world but not in the world of science. Franklin, the American statesman, was a respected scientist in the 1750s. As the story goes, he got two light strips of cedarwood, big enough to cover a large silken handkerchief. He then tied this to a hemp string, with a key tied at the end. Franklin attached a metal rod to top of the kite in hopes of attracting lightning – history’s first lightning rod – and tied a silk ribbon to the end of the string and key.

As the story goes, Franklin flew the kite into a thundercloud where the kite was struck by lightning, which ran down the string, jumped off the key and was trapped in a glass where Franklin intended to “store” electricity. However, the idea that a person holding a string at the end of a kite struck by a 100-million-volt lightning bolt would even survive is impossible, as would be “trapping” lightning’s current.

The myths about lightning are as varied as the people who relate them, but the facts that taking shelter in a house, other structure or a hard topped, fully enclosed vehicle during a thunderstorm are certainly true. Having the ability to separate lightning fact from fiction is certainly important. Like the myth that lightning never strikes twice in the same place. The fact is lightning does strike twice in the same place and does so repeatedly. For example, hundreds of lightning strikes per hour have been reported to illuminate the sky above the intersection of the Catatumbo River and Lake Maracaibo in northwestern Venezuela more than 300 nights a year, often flashing several times a second triggered by warm trade winds from the Caribbean Sea mixing with cool air descending from the Andes mountains.

Another dangerous myth is that surge protection devices can shield electrical equipment against lightning. The fact here is that surge arresters and suppressors are important components of a complete lightning protection system, but they cannot protect against a direct lightning strike.

Learn how to protect your electronics from power surges caused by lightning.

Throughout human history, lightning has generated fear and awe, and for good reason. Its tremendous power can spark vast forest fires, blow out the electricity of an entire city, and stop a person’s heart. As we continue to study the science behind lightning, we continue to enrich our knowledge and understanding of this immense force – and discover better ways to protect ourselves from its destructive power.