The hair raising truth about lightning

Travelling at 93,000 miles per second, discharging 30,000 amps and searching for the quickest route to ground, being caught in a lightning storm is literally like dodging nature’s swiftest assassin. With no idea whether this killer might strike, only the clap of thunder alerts you to the presence of this destructive phenomenon. Whether you believe lightning to be an artefact of Zeus’ rage or you are more familiar with the laws of energy transfer, one thing is certain- the lightning lottery is one jackpot it’s better not to win…

Lightning storms are a common global occurrence. This very second there are 1800 storms in progress around the world unleashing an incredible 100 lightning strikes per second. Unsurprisingly, with nearly 7 billion humans on the planet, we occasionally present a target to some of these bolts. But it’s not just ramblers, campers and other outdoor enthusiasts who become unwitting victims of lightning strikes – 52% of lightning related injuries occur in the home through telephone cables, televisions or metal taps. Dishes or death? The perfect excuse to abandon the washing up when there’s a thunderstorm afoot!

So what are the chances of being struck by lightning? In the UK, 3 people are killed by lightning each year, with a further 50 people injured. This puts the likelihood of being struck at 1 in 1.2 million, with a 1 in 19 million chance of fatality. Pretty low odds. Despite this, the Guinness World Record for surviving the most lightning strikes is awarded to Roy ‘lightning conductor’ Sullivan, who was hit by, and survived, an astonishing seven lightning strikes between 1942 and 1977. An immense mockery to the adage that lightning never strikes twice.

Mention ‘lightning strike’ and it conjures up images of the classic ‘danger of death’ logo; a jagged thunderbolt hurled from the heavens. Yet it’s not always a direct strike that causes the damage. Side flashes can occur when a person is touching, or stood next to, an object hit by lightning as they form part of the discharge pathway. Fifty percent of side flashes occur when trees are used to shelter from lightning storms. Current radiates outwards from the point of the strike and contacts within the radius determine the route that the current takes between two points. Legs, for example, provide the perfect bridge for current to travel between two feet…

Assuming astraphobia (the fear of thunder and lightning) is not fast persuading you to abandon your lightning education, it is worth taking a minute to consider the science behind this phenomenon. Lightning is the product of electrically charged storm systems although the exact cause remains unknown. One theory proposes that lightning is caused by the loss of electrons from water molecules during cloud formation. Collisions between rising water molecules cause them to lose electrons and become positively charged. Lower portions of the cloud retain the negative electrons creating a charge separation. The resulting electric field surrounding the cloud is responsible for the unusual tingling sensation reported by people who have experienced lightning storms. It quite literally causes your hair to stand on end; the negative base of the lightning clouds repels electrons in your hair causing the ends, now positively charged, to become attracted to the clouds. Nature’s very own Van de Graaf generator.

> It quite literally causes your hair to stand on end.

During a thunderstorm, public advice from the Met Office includes unplugging non-essential appliances, avoiding the telephone and, if you are outside, seeking low-lying shelter away from water, metal and tall objects. Should you find yourself in an exposed location, you are advised to crouch low with as little of your body in contact with the ground as possible. Hands on knees, head tucked in. It’s at this point you’ll realise that the Twister training has paid off. Sadly activities such as golf, angling, or boating are also ill-advised as the metal rods involved are lightning friendly. And lightning, as we’re realising, is not man’s best friend despite how pretty it looks in our holiday snaps.

A tactical approach to avoiding lightning misfortune would be to avoid the places where lightning is commonly found. The most obvious place being in the middle of a thunderstorm. Geographically, summer lightning hotspots in the UK include the Southeast, Midlands and East Anglia and are caused by warm air from the continent. Alternatively, during winter months, lightning is more commonly seen near the warmer waters of the Southwest peninsula. However, wherever you are, it is worth bearing in mind that if you can hear the thunder you are already in range of the lightning which can strike more than 10 miles away from the storm. Likewise, brandishing your brolly at an approaching thundercloud may not be the best way to thwart the impending storm as rain may not be its only weapon.

So how many seconds away is this assailant when the thunder booms and is it already too late? For the keen mathematicians amongst you it is possible to calculate how far away a thunderstorm is by the time between the lightning flashes and thunder. A lightning strike, at 30,000ºC, is hotter than the sun. So much so, it causes the surrounding air to explode in a shockwave of thunder. Light travels quicker than sound, therefore, the lightning flash will appear almost instantly whereas the sound wave from a thunderclap, travelling at 331.3 metres per second, will cover roughly 1 mile in 5 seconds. Following the lightning flash, divide the number of seconds until the next rumble of thunder by 5 to calculate the distance of the storm in miles. Admittedly, the speed of sound is affected by temperature and humidity and if you work in metric you may still be working out the distance conversions when the answer hits you with a flash of light… For the more innumerate, perhaps take this time to indulge in the sheer, sky-splitting volume of the thunder and just pray the figures work out.

So now that you are enlightened about, well, lightning, you’ll be sure to notice the tell-tale signs. Perhaps it’s worth getting some fluffy, non-conductive hand warmers for use with those metal golf clubs or wearing extra thick rubber-soled wellies on your next fishing trip. Or failing that, just wait until the hairs on your neck start to rise and realise that it’s probably time to scarper.

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