Lightning is one of the most common weather phenomena- it’s estimated that 100 strikes hit the Earth every second, yet it’s one of the most misunderstood. I’d like to change that by clearing up some myths and misconceptions about lightning in this week’s Moment of Science!
ESTIMATING HOW FAR LIGHTNING STRIKES
We’ve all done it- trying to figure out how far lightning is from us by counting the seconds between the strike and the roar of thunder. I’ve heard different conversions but the correct one is 5 seconds between light and sound= 1 mile away from the lightning.
This works out as thunder and lightning go hand in hand. Thunder caused by the rapid expansion and contraction of air as it’s superheated by lightning- creating that sound which travels roughly a fifth of a mile per second. This speed does vary slightly but even then do not use this method to gauge if you are far enough away from a storm to be struck- if you can hear thunder- you are at risk for being struck by lightning.
Heat lightning is not special or a different type of lightning- it’s just lightning from a storm that is too far away to hear the associated thunder. Sound decays the further from the source due to clutter like trees as well as the natural curvature of the Earth. Thunder really can only be heard at or less than 10 miles away from the lightning strike. At night when it’s much easier to see- more people are outside of that zone.
LIGHTNING NEVER STRIKES THE SAME SPOT
Not true. Lightning often strikes the same spot multiple times, especially if it is the tallest object. Think why we put up lightning rods- it would be pretty silly if they were single use only. The Empire State Building gets hit roughly 23 times per year.
STUCK IN A FIELD
This is a source of contention because if you’re doing everything right- you won’t find yourself in an open field with no shelter nearby in a thunderstorm. Older courses of action would have you become the shortest object by lying on the ground. This is no longer recommended as it increases your chances of injury or death by ground current from a lightning strike- which can spread out over 50 feet from where the lightning strikes the ground. If you are caught out in a storm- continuing moving to safe shelter.
You should know not to get under a tree- it’s the second leading cause of lightning fatalities. As it can both attract lightning… and explode as the water in the tree is boiled instantly. Heading inside is the best choice- but be sure to stay away from windows.
If a structure is not nearby- a car with a metal roof is the next best choice. This does not include ATVs, convertibles, or golf carts. Cars protect you by redistributing the lightning’s charge away from the interior down through the metal frame to the ground. It is not because the tires are rubber and act as insulation. Rubber soled shoes will also not protect you from lightning’s effects.
Storm Team 2 Meteorologist David Dickson