Lightning Safety

By Mary Ann Cooper, MD

For over 100 years, lightning has killed more people on average every year than hurricanes or tornadoes. The reason that more people don’t know about this is that most injuries occur to single people doing things that they do every day like waiting on a school bus, walking to work, playing soccer, or mowing the grass, not with huge weather changes like tornadoes and hurricanes cause.

NO PLACE outside is safe when thunderstorms are in the area. The easiest way to tell if lightning is close enough to hurt you is easy. If you can hear it, the next strike can easily come in your direction to cause you injury. Hearing thunder means that it is no further than ten miles from you. That’s why the National Weather Service and others teach the simple rule: “When Thunder Roars, Go Indoors”. There are times that you can see lightning so far away that you don’t hear its thunder. But if you can hear thunder you are already in the ‘danger zone.’

At the first sign of thunder, you should start heading for a safe place. Safer places mean a building that is large enough for someone to live in like a house, library, school or other substantial building. Another very safe place to be is in an all metal vehicles like a car or bus with the windows rolled up. One of the most common places for someone to be injured is near or under a tree where they have usually gone to avoid getting wet. Nearly any place that is called a ‘shelter’ is not safe from lightning. That includes bus shelters, rain shelters, beach shelters, golf shelters, picnic shelters, etc.

Lightning can also cause injury inside a building if it hits close to it and is carried into the building through the plumbing or wiring. This is especially true for computers, game stations that are hard wired, or the old fashioned hard wired telephones. In Wonderstruck, Ben is injured while speaking on the phone during a thunderstorm, and many people have lost some of their hearing from such events. You can even be injured in a swimming pool whether it is an outdoor or indoor pool for the same reason – energy gets carried inside through the wiring for the lights, pumps and heaters.  This is called a ‘contact’ injury because the person is in contact with something that is transmitting the energy.

If you are standing on the baseball field, lightning can hit some distance but be carried to where you are standing (called ground current, step potential and many other technical names) and injure you and most of your teammates. In fact, probably more than half of all injuries occur this way. The next most common way someone is injured is if they are standing close to something that is hit like a tree, bleachers, a fence or a flagpole. Part of the lightning can ‘splash’ across to people and cause injury while the rest of it continues through the thing it hit first.

Less than 5% of people are actually hit by a ‘direct’ strike – one that comes out of the sky and hits a person directly instead of going through something else.

There a many myths about lightning. The biggest myth is that everyone dies. Only about one in ten people who are injured by lightning are killed. Nine out of ten people survive but they can permanent problems including brain injury that keeps them from remembering things and doing well in school or have constant pain that lasts for months or years. These problems can also keep people from going back to work and from being able to doing the things they did before the injury like play golf or baseball.

Many people think that because lightning has so much energy in it that it must cause terrible burns.  Actually, only about one in three survivors have any marks at all on their skin and any burns are usually no worse than a bad sunburn. This is because lightning is so quick that it’s not around long enough to cause skin damage. It is also probably because most lightning injuries are indirect like those from contact injury or ground current.

Another big myth is that metal or a person can ‘attract’ lightning. Lightning rods do not attract lightning. They carry the lightning from something that is hit down to the ground safely rather than letting it go through the building and cause a fire, burn up all the electrical systems or cause other damage. Lightning is statistically more likely to hit tall things or something that is in an open area, but nothing can actually attract lightning or cause it to hit a specific object. Nothing you wear, touch or do will attract lightning to you and people who claim they ‘attract’ lightning are mistaken (feel free to suggest a stronger statement if you wish!). However, if you are standing close to something tall like a tree, out in the middle of a football field or a pasture, or standing in a canoe in the middle of a lake, you are certainly taking a risk that lightning is going to see you as an attractive target if it is coming down close by. That’s why we teach “When Thunder Roars, Go Indoors”!

Many people make the mistake of going outside again before the thunderstorm and danger of lightning has completely passed. A simple way to remember when it is safe to go outside and resume activity is “Half An Hour Since Thunder Roars, Now It’s Safe To Go Outdoors”.

Lightning can hit even if the rain has not started where you are. Lightning can easily hit ten miles or more from the thundercloud where it started.

The best way to prevent lightning injury is to be aware of the weather forecast for the area you plan to visit and make alternate plans if thunderstorms are predicted. For unexpected storms you should also have a ‘lightning safety plan’ that includes where the safer places (substantial building or metal vehicle) are located and how long it will take you and your friends to get there. Always having a “weather eye’ or ‘an eye to the sky’ to see if thunderclouds are rolling in and if lightning is present is a good idea. And remember “When Thunder Roars, Go Indoors” and “NO PLACE outside is safe when thunderstorms are in the area.”


Mary Ann Cooper, MD, retired professor of emergency medicine at the University of Illinois at Chicago, is the recognized international authority on lightning injuries and injury prevention.  For more than thirty years, she has worked with electrical and lightning injury survivors and their families, writing and teaching about these injuries and working with the National Weather Service and weather broadcasters on lightning safety (www.lightningsafety.noaa.gov).  She is the only physician to have ever been awarded Fellowship by the American Meteorological Society and also received an AMS Special Award for her pioneering worldwide educational work on lightning injury and lightning injury prevention.