A lightning bolt struck 91 people at a car racetrack in Norway on Sunday. The lightning hit a stadium and hurled spectators from their seats while others ran in panic. A fleet of ambulances and helicopters ferried the injured to hospitals in Flisa, near the Swedish border, but there were no serious injuries.

There have been many instances of open sports stadiums hit by lightning. But, according to a study in the US, the threat from lightning strikes is not just the lightning itself, but also crowd control. In 1998 lightning struck a concert in a stadium in Washington DC, killing one of the audience and setting off mass panic among the crowd that caused more injuries in narrow exit tunnels. Stadiums are now advised to plan for swift mass evacuations.

In the UK, one of the worst lightning strikes in a sports arena was at Royal Ascot on July 14, 1955. On a hot and muggy day, a thunderstorm broke during the afternoon and sent crowds rushing for shelter as rain pelted down. Soon afterwards lightning struck a metal fence and, even though no one was struck, the voltage gradient from the lightning ripped through the ground and scythed down crowds packed in and around a nearby marquee. The aftermath looked like a battlefield, as the injured lay on the ground and others wandered around dazed and shocked. Two spectators died and 48 others were injured.

Possibly the world’s worst sporting tragedy caused by lightning was in 1998, when an entire football team were killed and 30 others injured during a match in the Democratic Republic of Congo, one of the most lightning-prone places in the world.