Project Cumulus

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Operation Cumulus was a project of the UK government in the 1950s which was investigating weather manipulation, in particular through cloud seeding experiments. Known jokingly within the project as Operation Witch Doctor,[1] the project was operational between 1949 and 1952.


The military were controlling the weather for several reasons, as detailed in minutes of an Air Ministry meeting held on 3 November 1953.[1] They included:

  • "bogging down enemy movement";
  • "incrementing the water flow in rivers and streams to hinder or stop enemy crossings";
  • clearing fog from airfields.

The Lynmouth disaster[edit]

Main article: Lynmouth Flood

On 16 August 1952 a severe flood occurred in the town of Lynmouth in north Devon. 9 inches (229 millimetres) of rain fell within twenty-four hours[2] "Ninety million tonnes of water swept down the narrow valley into Lynmouth" and the East Lyn River rose rapidly and burst its banks.[3] Thirty-five people died and many buildings and bridges were seriously damaged. According to BBC, "North Devon experienced 250 times the normal August rainfall in 1952."[3]

A conspiracy theory has circulated that the flood was caused by secret cloud seeding experiments conducted by the RAF.[4][1] The theory has been dismissed as "preposterous" by experts.[5]

See also[edit]


  1. ^ a b c Vidal, John and Helen Weinstein, RAF rainmakers 'caused 1952 flood', The Guardian, 2001-08-30, retrieved 2007-07-21.
  2. ^ 1952: Flood devastates Devon village, BBC
  3. ^ a b Rain-making link to killer floods, BBC, 2001-08-30, retrieved 2007-07-21
  4. ^ Hilary Bradt; Janice Booth (11 May 2010). Slow Devon and Exmoor. Bradt Travel Guides. p. 249. ISBN 978-1-84162-322-1. 
  5. ^ The day they made it rain, Philip Eden, WeatherOnline