Hiding in plane sight: the invisible turbulence that can strike out of a clear blue sky

As the planet warms, airlines are grappling with what this means for air travel – and for the passengers who simply refuse to keep their seatbelts fastened It was a swelteringly hot afternoon in south-west Myanmar on 21 May 2024. Tropical thunderstorms, showers and highs of 36C were forecast for the area around the Irrawaddy Basin.

High above, monsoonal heat and humidity were building into a vast convective column of water vapour, a towering cumulonimbus cloud soaring up to 35,000ft (more than 10,500 metres) into the air. From the ground, it would have looked like something from a children’s picture book – a soft, fluffy white mass. But for Singapore Airlines flight SQ321 passing just above, it was anything but benign. In the cabin of the Boeing 777, passengers were being woken up for breakfast with three hours to go on the journey from London to Singapore. For the 210 travellers on board, the past 10 hours had been uneventful. The seatbelt signs were off. Some were milling around, others were using…