"Lightning isn't dangerous if you know how dangerous it is"

"Yes, absolutely," says Laila Fodnes Sidselrud.

She is a meteorologist who works with the Norwegian Meteorological Institute's lightning observation service. 

"It's like many other things in life. Lightning isn't dangerous if you know how dangerous it is. You need to respect it and take precautions. You need to remember what lightning actually is: A very powerful, electrical spark," she says.

According to lightning expert Oddgeir Rokseth, senior technician at SINTEF, Norway sees about one lightning-related death every four years. 

"The risk is small. Lightning is quite 'short-sighted,' so a person makes up a very small elevation in the terrain. But if you're truly unlucky, the consequences are that much greater," he says.

One golden rule

Advice about lightning safety often surges during thunder-heavy summers. Oddgeir Rokseth always recommends that people seek shelter – ideally indoors or inside a car.

"If you can move away from the storm, even if it's just walking in the opposite direction, you reduce the risk. Thunderstorms are constantly moving, clouds shift, and conditions are unstable. Predicting the exact strike point is nearly impossible. I call it bad luck," he adds.

Sidselrud summarises the advice as follows:

"We're safer indoors than outdoors when it comes to lightning. And summer doesn't have to be dangerous. It all comes down to one simple rule: Never be the tallest point," she says, giving a practical example:

Seek a ditch

"When a thunderstorm hits and the rain pours down, don't be tempted by that tall birch in the middle of the field just because you could stay dry underneath it. The tree is the highest point, and if lightning strikes it, the current will be transferred to you as you sit with your back against the trunk. Likewise, don't risk walking back across the open field and becoming the highest point yourself. I recommend a ditch! You'll end up soaked, but you'll be relatively safe," says Sidselrud.

"They say that squatting is best?"

"Yes, as long as you squat with your feet together. That way, the current won't travel up one leg and down the other, which could happen if your legs are spread apart, forming a bridge. That's why reindeer and cows are more at risk. The current can enter through their front legs, exit through their back legs, and pass through the heart. Lightning often strikes close to animals and travels along the ground. But how long can you manage to squat? If you find a ditch or a narrow crevice, it might be better to lie down in it," she says.

Dangerous mountains

Mountain hikes are popular in the summer, and that's where you're most exposed. A few years ago, two hikers lost their lives on a summit trip in Norway.

"If you're caught in a thunderstorm on a mountain and haven't reached the top yet, don't push on – head down immediately. Get low! I've heard stories of hikers feeling their hair stand on end. That's not the time for a selfie, but rather to get down quickly. It means the thundercloud has built an electric field that lifts your hair," says Sidselrud.

Laila Fodnes Sidselrud explains that lightning forms what's called a channel: one from the cloud, one from the ground. Hair standing on end can be a warning sign that this is happening. When the two channels connect, the current is released.

Rokseth says that even if the lightning channel forms just a few metres away, the force can knock you off your feet. If it passes through your body, for example from your arm to your foot via the heart, you're in serious trouble. It's a large current, a lot of energy, concentrated in a small area, he explains.

From a clear sky?

Lightning doesn't strike from a clear sky – except in very rare cases. This happened in the USA, where the main thundercloud was in the neighbouring valley, but a small wisp stretched over and caused a lightning strike. 

Still, lightning expert Sidselrud says thunderstorms should not stop people from enjoying the outdoors.

"Watch the clourds. If one's directly overhead, that's when you need to be most careful. But even when you just hear rumbling, you should start moving to safety – off open fields, out of the water. Don't sit down with your fishing rod when you hear rumbling either, as it's pointed and tall," she says.

"What about umbrellas?"

"Then we're back to whether it becomes the highest point. The same applies to people on a golf course about to swing a club – you're relatively tall compared to your surroundings. Don't think you can 'just' finish the round," warns the meteorologist.

Festivals

In festival settings, taller structures like spotlights and stages usually draw strikes first. Last year, two festival evenings, Tons of Rock in Oslo and By The Pond in Sandefjord, were stopped when there was a storm and risk of lightning.

"I think many festival organisers keep a close eye on this and feel responsible for their audiences. I sometimes hear from organisers asking whether there are special alerts or statistics on how often something happens," she tells NTB.

When asked whether lightning apps and websites can be trusted, Laila Fodnes Sidselrud recommends Yr's lightning map.

"There we capture most of what's happening in Norway, at least in summer," she says.

More lightning to come

Indoors, you're generally safe from lightning. But unplug any charging cables before making a call during a storm. Cars are also relatively safe. Not because of rubber tyres, but because they acts as a cage that channels the current around you. The same rule about unplugging charging cables applies there, too.

It's worth learning the most important lightning advice, because research suggests that we can expect more lightning in the Nordic countries in the future due to climate change. Warmer temperatures, longer summers, and more showers increase lightning activity. 

"Whether we've reached that point is hard to say. We’ve been tracking lightning since 2000, but the yearly variations are huge, and changes to sensors and software make it difficult to pinpoint long-term trends," she says.

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Translated by Alette Bjordal Gjellesvik

Read the Norwegian version of this article on forskning.no

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