In 1977, a US project used satellites to monitor the globe for nuclear explosions, but they unexpectedly caught intense flashes of light a thousandth of a second long. These were lightning superbolts, the most powerful lightning on Earth, 100 times more powerful than typical lightning and capable of causing serious damage.
Superbolts are rare – less than 1% of all lightning – and what creates them has long been a mystery. But a study of superbolts across the globe revealed three hotspots where superbolts were most frequent: the north-east Atlantic, the Mediterranean and the high-altitude Altiplano plateau across Peru and Bolivia.
These areas are where thunderstorms can be fairly compact and lie closer to the surface of the sea or land. The electrical energy in a lightning bolt is generated in the freezing upper reaches of a storm cloud where temperatures are 0C or lower, and the superbolt hotspots had one thing in common – the level of 0C in the storm clouds lay unusually close to the surface below. So, when a storm let rip, the lightning had a shorter pathway to pass through with less electrical resistance, and a more powerful current could zap the ground.
