On 8th of August 1975, about one hour after midnight, the Banqiao dam failed.
A tidal wave of water 10km wide, over 5m high and travelling at up to 50km per hour raced across flat farmland in Henan province, China, demolishing everything in its wake.
It tore up roads and bridges, power and communication lines. Whole villages were swept away. As the torrent continued downstream, more dams failed, one after another, like dominoes.
An estimated 230,000 people drowned.
For those who survived the initial disaster, the relief effort was slow to arrive and came too little and too late. Over 10 million people were displaced, many of them dying of famine and disease.
The official explanation was the weather. Typhoon Nina blew in from the south, meeting a cold front from the north and a year’s worth of rain fell in twenty-four hours. As the reservoir level rose, the authorities forbade the release of water for fear of flooding downstream.
The dam was poorly designed. Constructed in the 1950’s as part of China’s modernisation program –The Great Leap Forward — cracks and leaks began to emerge. The response was to reinforce it to Russian specifications. The new “iron damn” stood firm against the monstrous risk that was building until it was overwhelmed by a freak weather event.