Is lightning less dangerous when you’re wet?

Research suggests that getting caught in the rain and having a damp head may make getting struck by lightning more survivable.

Being wet when struck may help the lighting travel over the skin instead of through the body. Picture: istock

The seas, George remembers, were a “wind-whipped nightmare”. On deck that day in 2010, it was “pouring buckets of icy cold rain”. Between his boat and the safety of the North Carolina beach there was a waterspout. Struggling to maintain control, soaked to the skin, he did not have time to think about the sudden hot flash he felt.

It was only when driving home that he smelt the singed hair and saw his burnt face. He had, he realised, been struck by lightning.

Now research has pointed to a possible reason he not only survived that day, but stayed conscious: the rain. Scientists who used models of human heads to investigate the effects of lightning, measuring current both on the inside and the outside of the models, found that if the head was damp the current was more likely to propagate on the surface.

Despite being proverbially unlikely, lightning can be a real risk in some professions. Roy Sullivan, a US park ranger known as the Human Lightning Rod, holds the world record for the number of lightning strikes on one person (seven). Surviving that many is not as implausible as it might sound. Between 70 and 90 per cent of people are believed to survive a lightning strike - although suffering as many as Sullivan is far from recommended.

Rene Machts, from Technische Universitat Ilmenau in central Germany, said he was inspired to find out why people do and don’t live - not least in the hope of improving the odds.

There had been little investigation of the effect of water, although in the mid-1980s an intriguing (and today probably unallowable) experiment in rats found that those who were wet were more likely to survive simulated lightning.

If you are unlucky enough to be struck by lightning, then what you want is for your body to act as close as possible as a Faraday cage; you want the electricity to find a route to earth by travelling over your skin rather than through your organs. This is known as a surface flashover. Machts’s hunch was that being wet improved the likelihood of an efficient flashover, by increasing the conductance on the skin.

In a study published in the journal Scientific Reports, Machts and his colleagues found that when a wet model head was struck by simulated lightning, the electricity formed a flashover more readily. The electrical energy inside the skull was a third lower than for the dry targets; there was also less visible damage. Afterwards, when they inspected the wetter models’ skull the researchers also found fewer burns and cracks. Even so, it was clear from the aftermath of the impact that however wet your head is, getting hit by lightning is not a good idea.

Thankfully for George - whose story, but not surname, is recorded in a collection of lightning survivor tales by the US meteorological service - there is still the possibility of escaping relatively unscathed. On reaching shore he dithered about whether or not to go to the hospital, eventually deciding against it. “They’d probably keep me overnight for observation,” he explained. “And they don’t serve beer.”

The Times