Types of Lightning

My grandfather was a college physics professor who devoted his life to lightning research. He was the first person in the world to photograph ball lightning and prove its existence.  I grew up in a household where electrical theory was a common dinner table conversation, but the most memorable teacher on the subject of lightning was Mother Nature herself. 

I was eight the summer we visited my grandparents in Lincoln, Nebraska.  There was a huge thunderstorm brewing. We could hear thunder in the distance and my brother and I sat and counted the time between boom and flash. “One, two, three, four, five, six…” FLASH! The sound of thunder travels a mile in 5 seconds, so this one was getting close. The rain came and then subsided. We thought the storm had passed over. I went to bed. An hour later, a crashing noise so loud it woke me in terror just in time to open my eyes and see blinding light right outside my upstairs window. Everyone was scurrying around the house, calling to each other to make sure we were all okay. Eventually the storm passed and we went outside, drawn by the fire trucks racing down the street. Lightning had split the elm tree outside my window in two. Fortunately, it hadn’t fallen on the house, but at the end of the street, a small grocer wasn’t so lucky. Lightning zipped into his store and on its way to ground cremated everything on the way. The next morning, the poor man stood outside his charred rubble selling “lightning-baked potatoes” for a nickel. We bought one as a souvenir. 

Lightning, a gigantic spark of 100 million to 1 billion volts of static electricity is formed when rain clouds are negatively charged at the base and positively charged at the top. Ice in the clouds seems to be the stimulus for forming lightning as ice has a negative charge while water droplets maintain a positive charge. Sometimes large drops of water become negatively charged while small ones carry the positive charge. Lightning occurs when the negative charge at the base of the cloud discharges its energy toward the positive charge of earth below it… and heaven help anything in the path. 

Conductors – substances through which electricity can pass quickly – hurry the trip to earth. Water and metal are excellent conductors. Anything tall will be struck first as in the case of the tree next to my window. Humans, being mostly water, are excellent conductors. A tall human on a flat surface like a field is at risk. When lightning strikes the ground, its charge can spread out quite a distance if there is a conductor like water present. That’s why you don’t want to be swimming or standing in water outside.  You don’t even want to be in the bathtub or have your hands in a sink of water in case lightning electricity comes into the house via metal pipes. 

Lightning shows its fury to us in multiple forms. The most common is Cloud to Cloud. When the entire sky lights up because of it, it’s called Sheet Lightning. Then there is cloud to ground when the static electricity within the cloud finds a speedy conduit via moisture to the ground. Ball Lightning, which made my grandfather famous, has often been dismissed as the viewer’s imagination. Fiery balls seem to dance in the sky.  There have been all sorts of theories as to what their cause may be, but recently, two New Zealand researchers may have come up with an answer. Their studies suggest that lightning striking the earth stirs up silica causing a vapor that may condense into particles that when combined with oxygen in the air burn slowly causing those mysterious orbs. 

Each second, there are 50 to 100 cloud to ground lightning strikes in the world. Most of them average 2-3 miles in length and carry a charge of 10000 amps at 100 million volts. You don’t want to be in the way, but many people do die as lightning is the number one cause of storm-related deaths.  In the U.S., 200 people die a year from lightning and 750 are seriously injured. 

The antidote to being an electrical conductor is to be insulated. Being inside a wooden structure is good. Your car is also a safe haven but not because it has rubber tires. Your safety depends upon the fact that the electrical current will travel along the outside of the metal body of the car and dissipate into the ground via the tires and rainwater. Just make sure you stay inside until the storm is past and that you stay there until you are sure there 

Of course the best place to be is inside an insulated house, not in the bathtub or on the phone. From your viewing position on the couch, you can watch the beautiful scene that Mother Nature gives us with lightning.  “Was that cloud to cloud or cloud to ground?” you ask your family. Then thunder claps again and you begin the count. If you’re lucky, you may even see the mysterious ball lightning.