Why Lightning is Deadly?

When we travel by plane the cruising altitude is always above the clouds (at around 12.000 meters high). If your flight is on a full sunny day and you look downwards though the window at that height you either see the ground below or a white blanket of clouds. But that will quickly becomes boring, you conclude that there is nothing special with those clouds. The only interesting part of your flight is when the plane is taking off and when the plane is landing, that to moment most passengers are curious to look out the window. Once you are at cruising altitude you might even become sleepy or you’ll choose to do something more entertaining instead, such as read a book, watch a movie, listen to music or just simply take a nap.

Me too, I do the same most of the time during my flights. Yet on multiple occasion during my trips by plane I was curious to look closely at the clouds mostly when the my plane was descending. And so I realized that clouds are natural formations comprised of liquid droplets of “almost” pure water. The “almost” bit is interesting; it’s the reason why rainwater isn’t pure, why windows get stained by rain, and why fog forms in some places and not others. Pure water is fine, but the water in clouds has somethings else in it. The water in clouds is neither pure nor innocent—it can kill. If enough clouds get clumped together that could easily turn into a heavy rain with thunder and lightning.

HOW STORM CLOUDS FORM?

Storm clouds are formed under a very particular set of circumstances. The process of thundercloud formation starts with vaporized water (H₂O), which moves around as a gas. In the chaotic, turbulent atmosphere, this doesn’t happen easily as it does in a regular white cloud formation, but the process is expedited by the tiny bits of particulate matter that are already in the air —often small bits of dust that have blown off trees and plants, or smoke from factory chimneys. The H₂O molecules can attach themselves to these particles, and as more and more of them join together, the particle becomes the center of a tiny droplet of water. This is also why when you collect rainwater, it generally contains sediment, and why when the rain dries onto your car windshield or the windows of your house, it leaves a fine powder. As these droplets experience cold air, water vapor changes from a gas back into a liquid. It’s the opposite of what happens when your wet clothes dry on a clothesline. In doing so, it gives off energy in the form of heat—we call this latent heat.

Latent heat is emitted from H₂O molecules while they’re still inside the cloud, meaning the air in the cloud gets warmer. As we know, warm air rises, so the cloud bulges out at the top. That’s how puffy cumulus clouds are made. But if all that happens while a lot of warm, humid air is rising up from the ground—as might happen on a summer’s day—then the convection currents pushing the cloud droplets upward might be strong enough to reverse the rain and send it upward too; the droplets will go few thousands of meters into the sky, until the air carrying them finally cools enough to stop rising. That high up in the atmosphere, the rain droplets freeze, become ice particles, and then fall again, but depending on the climatic conditions, they might be pushed upward again by still more warm air. Meanwhile the cloud is getting bigger and taller, and darker and darker, a cumulus cloud being transformed into a cumulonimbus cloud —a storm cloud.

The convection currents pushing the droplets up increase to speeds of 100km/h, and the cloud becomes a complex swirl of activity, with ice particles falling through an updraft of air that’s carrying still more droplets, all of which are colliding violently over several  kilometers.

The scientific community still isn’t sure how the conditions inside a cumulonimbus cloud lead to the buildup of electric charge. But we do know that, as it does on the ground, the electricity arises due to the movement of charged particles, which originate from atoms. All atoms share a common structure: a central nucleus containing positively charged particles called protons, surrounded by negatively charged particles called electrons. Occasionally some of the electrons break free and start moving around; this is the basis of electricity.

When you rub a balloon on a wool sweater, you create charged particles on the balloon. Then, if you hold that balloon up to your head, your hair will move in response to the charges on the balloon, attracting the opposite charges on your hair. Negative charge ultimately wants to be reunited with positive charge, and it stretches your hair toward the balloon in order to accomplish this, causing your hair to stand on end. If the amount of charge were higher, there would be enough energy for the charged particles to jump through the air, creating a spark. In a cloud, instead of gently rubbing balloons you have water droplets and ice particles, all turbulently crashing into one another with tons of energy, giving some of the ice particles a positive charge as they’re carried to the top of the cloud, and some of the raindrops a negative charge as they fall to the bottom. This separation of positive and negative charges over many kilometers of cloud is driven by the energy of the winds inside the cloud.

But the attractive force between the positive and negative is still there—they want to get back together, which is to say there is a voltage building up inside the cloud. It can get so large, reaching hundreds of millions of volts, that it strips electrons away from the molecules in the air itself. When this occurs, it happens very quickly, triggering the release of an electric charge that flows between the cloud and Earth, or between the top and the bottom of the cloud, depending on the conditions. The discharge is so big that it glows white-hot –it’s lightning.

And thunder is the sonic boom of the surrounding air rapidly expanding as it’s heated to tens of thousands of degrees °C in temperature.That can even generate a little bit of antimatter as well. (which by the way just for info: the antimatter is the opposite of mater/ that means when the 2 collide with each other, a complete annihilation of everything in the surrounding environment occurs, the result being only a massive amount of energy in form of X-rays and gamma-rays). The energy of lightning is so huge that it can and does vaporize people, hence the high death toll.

WHY LIGHTNING IS DEADLY?

It is well known that electricity always flows down the path of least resistance—it’s like a liquid in that respect. But while liquids flow down gravitational fields, electricity flows down electric fields, and since air doesn’t conduct electricity very well, it has high resistance to the flow of electricity. Humans, on the other hand, are composed mostly of water, which does conduct electricity well. So if you’re a lightning bolt emanating from a thundercloud, trying to find the path of least resistance to Earth, a person is often your best vehicle. While lightning might prefer to go through a tree because it’s taller and longer, and thus more of the conductive path can go through its watery branches, if a person is sheltering under that tree, then the lightning might, and often does, jump over to the person on the last part of its journey to Earth.

Night and day, somewhere on the planet, lightning storms are raging, at a pretty constant rate of 50 lightning flashes per second, globally. It’s estimated that there are more than a 1000 human deaths by lightning per year, with the injured numbering in the tens of thousands. The US National Weather Service keeps a running total of the deaths, and the particulars of the fatalities.

The table below shows some of the entries for from 2016. You’ll see that taking shelter under a tree is not a good idea, and that danger can strike almost anywhere.

Throughout a lot of the world, the tallest structures are often buildings, and in the West, for a long time, the tallest building in any town or city was a church. Many early church spires were made of wood, and they would burst into flames when lightning hit them. Fortunately, in 1749, Benjamin Franklin realized that if you just placed a metal electrical conductor on top of buildings and connected that to the ground with a piece of conducting wire, you’d give the lightning an easier path down and thus avoid a lot of the destruction caused by lightning strikes. These conducting wires are still used today and continue to save hundreds of thousands of tall buildings from being damaged by lightning. The same principle explains why being inside a car protects you from lightning: if the lightning strikes the car, it will be conducted around the outside of the metal bodywork, a path less resistant than going through the passengers.