On August 15 1952, one of Britain’s worst ever flash floods swept through the village of Lynmouth in north Devon.
Nine inches (229 millimetres) of rain fell within a twenty-four hour period and thousands of tons of water flowed into the East and West Lyn rivers, destroying homes, bridges, shops and hotels. Thirty five people lost their lives.
Here is an eye witness account by one of the guests staying in the Lyndale Hotel:
“From seven o’clock last night the waters rose rapidly and at nine o’clock it was just like an avalanche coming through our hotel, bringing down boulders from the hills and breaking down walls, doors and windows. Within half an hour the guests had evacuated the ground floor. In another ten minutes the second floor was covered, and then we made for the top floor where we spent the night.”
Another guest reported:
“We were looking out when we saw three people being washed out to sea. We managed to get a hold of them and brought them through the window. By the morning boulders were piled 20 feet high outside that window.”
The disaster was officially termed “the hand of God” until government files were declassified in 2001, revealing that a team of international scientists working with the RAF could have contributed to the conditions that caused the flood. These documents exposed the fact that the ‘Operation Cumulus’ team was experimenting with cloud seeding in southern Britain at the time. Known jokingly within the team as ‘Operation Witch Doctor’, the project was operational between 1949 and 1952, but, until 2001, the Ministry of Defence had categorically denied knowledge of any cloud-seeding experiments taking place in the UK during August 1952.
Cloud seeding involved pouring various catalysts over clouds to induce heavy rains. RAF pilots, dubbed ‘rainmakers’, dropped salt, dry ice and silver iodide over the clouds and scientists monitored the resulting precipitation. Significantly, it was claimed that silver iodide could cause a downpour up to 300 miles away.
After the Second World War, the British government had been researching innovative ways to gain a technological edge over enemy forces. Manipulating the weather offered the prospect of thwarting attacks, clearing fog from airfields and bogging down enemy movement by, for example, hindering river crossings. There was also the potential to explode an atomic weapon in a seeded storm system to produce a far wider area of radioactive contamination than in a normal atomic explosion. Given what happened in Lynmouth, the experiments were working only too well.
Recalling the success of the experiments, RAF Group Captain John Hart told the BBC: “We flew straight through the top of the cloud, poured dry ice down into the cloud. We flew down to see if any rain came out of the cloud. And it did about thirty minutes later, and we all cheered.”
The BBC also unearthed a radio broadcast involving an aeronautical engineer and glider pilot, Alan Yates. Working with Operation Cumulus, Yates flew over Bedfordshire, spraying quantities of salt over the clouds. He was elated when scientists confirmed this had led to a heavy downpour fifty miles away over Staines, in Middlesex. “I was told that the rain had been the heaviest for several years – and all out of a sky which looked summery,” he said. “There was no disguising the fact that the seedsman had said he’d make it rain, and he did. Toasts were drunk to meteorology and it was not until the BBC news bulletin [about Lynmouth] was read later on, that a stony silence fell on the company.”
The declassified documents suggest that Operation Cumulus was active between August 4 and August 15 1952. Scientists based at Cranfield school of aeronautics were collaborating with the RAF and the MoD’s meteorological research facility at Farnborough. The chemicals were provided by ICI in Billingham.
Operation Cumulus was put on hold indefinitely after the Lynmouth tragedy. For years, rumours persisted that certain official documents had been deliberately destroyed and survivors of the disaster clamoured in vain for a full investigation into the causes of the flood.