The complicated science of getting struck by lightning
So, I nearly died a few nights ago.
There’s a saying that goes: "You never see or hear the one that gets you." Lucky for me, I both heard the sizzle of the bolt as it arced by my head and saw the blinding flash of the main strike as the circuit between cloud and ground was completed. The next thing I knew was someone was shrieking like a little girl and I was trying to burrow under the car like a demented prairie dog.
Yeah, that was a close call.
Actually, I’d been more than a little lucky. I’d been missed by both the main lightning strike and by the indirect impacts of a few million volts of electricity being jammed into the ground right beside me. Both can kill and so I’m guessing that Mother Nature decided I just needed a little reminding that she can get cranky at times, rather than an instant obliteration.
Lighting kills about 15 people in the United States every year, just behind the death toll from floods. Around the world, it’s anywhere between 6,000 and 24,000. Hard numbers are difficult to come by not just because records are spotty at best in some countries, but also due to the nature of lightning strike injuries.
At first thought, it seems like the enormous amounts of energy in a lightning strike should detonate a frail human body like any given vehicle in a Michael Bay action flick, but the reality is far different. Despite the huge amount of power involved, a direct strike on a human body rarely produces thermal burns. The current flow is generally too brief to heat up tissues, but it can vapourize metal that happens to be touching someone. There have been a few cases where someone wearing an iPod had burn injuries along the length of the ear-bud cables as the copper wires exploded.
The way that a direct lightning strike inflicts the majority of injuries is through electroporation and EMP induction. These have very different effects on the human body.
Electroporation occurs when extremely high voltage rips holes in the cell membrane of nerve and muscle cells. These holes don’t necessarily kill the cell, but if it’s a neuron, for instance, the chemical signals that the cells transmit may be disrupted. This can lead to neurological problems which often characterizes lightning strike victims. Muscle damage can also occur if the electroporation occurs in those cells as well as vascular damage that can lead to tiny clots of blood. These can lead to the death of cells and further larger scale damage.
But, unfortunately, it can get worse.
The EMP pulse of lightning bolt is the real killer. We’re a kind of biological machine that runs on electrochemical reactions inside the body. Slam a few million volts through it and while the majority of the charge tends to conduct around the outside of it, the EMP pulse can create surges that short out the nervous system, specifically the pacemaker system of our heart. The old myth about mechanical pacemakers and microwaves comes true here, but on a slightly more massive electrical current.
This is why some victims have been found with no external injuries, but are still dead. Lightning doesn’t even need to hit directly to kill you.
Indirect strikes can be far more deadly and are responsible for far more deaths than direct strikes. These are the ones that are the cause of headlines that read: “Five golfers struck by lightning…”
How this occurs is part of how lighting actually occurs. The process of a lightning bolt is quite complicated, but it basically goes like this; a charge differential (science speak for having a lot of positive and negative charges separate from each other) is built up between the thunderstorm cloud and the ground. When a channel or connection is made between the cloud and the ground, stupendous amount of electrons move between the two. This flow of energy moves through the ground towards the connection point and if you’re standing close, the electricity can take a path through you rather than through the ground.
The murder spark that tried to do me in was close, very close and as I said, I got very, very lucky. I managed to avoid both the direct strike and the effects of the indirect strike. I still haven’t figured out how close the bolt came to me.
So, how do you protect yourself from lightning? Check back on Monday for the answer.
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