FOI Request: 262 Pages on Weather Modification in the 1950s, 60s and Beyond
262 pages of reports, emails, and meteorological and scientific data reveal details on weather modification before, during and after Operation Cumulus, including links to the 1952 Lynmouth flood.
Last year, I submitted a Freedom of Information (FOI) request to the government, asking for the declassification of records on weather modification in the 1950s, specifically Operation Cumulus — the dry ice operation led by the RAF over Lynmouth, Devon, in 1952. This operation is believed to have contributed to the flash flood that killed 35 people.
Below is the request I made:
I am writing to submit a Freedom of Information (FOI) request to the Ministry of Defence regarding the subject of geoengineering and weather modification.
I am seeking information on the following topics:
Funding: Please provide details of any funding allocated by the Ministry of Defence or its affiliated departments for research, development, or implementation of geoengineering and weather modification projects, both past and present.
Military Involvement: I would like to know if the military is currently involved in any physical or simulated geoengineering and weather modification projects. This includes any collaboration with external organisations or research institutions.
Historical Context: Given the historical precedent of military involvement in weather modification activities, such as the RAF Lynmouth incident in 1952, also known as "RAF Rainmakers" or Operation Cumulus, I am particularly interested in any documents, reports, or information related to this event or similar activities conducted by the Ministry of Defence.
I understand that some of the information requested may be sensitive or classified. However, I believe that transparency in government actions related to geoengineering and weather modification is essential for public accountability and informed decision-making.
To my surprise, the Ministry of Defence complied with my request and provided 262 pages of information.
A note: It is unclear which of the provided documents have been recently declassified and which have been in the public domain for a number of years — the full document is available to view at the bottom of the article.
The Ministry of Defence has stated that they do not hold information for question 1 and question 2.
This document and accompanying findings were obtained through a freedom of information request to the Ministry of Defence. Some information within the document pertains to historical activities, including the names of individuals involved in Operation Cumulus and related experiments. These names were not redacted by the MOD and are presented here as part of the historical record.
All information has been shared in its original, declassified form (via the link to the proton drive) as provided by the MOD. Any redactions present in the document were made by the Ministry of Defence to comply with legal obligations under the Freedom of Information Act 2000, including the protection of personal data under the Data Protection Act 2018.
This article is intended for informational and journalistic purposes to encourage transparency and public awareness.
Key Summary of Findings:
Letter to Liberal democrat MP from the Met Office admits to Cloud Seeding before and after Operation Cumulus in 1952.
In a letter sent by the Met Office in November 2001, Liberal Democrat MP Norman Baker asked about the Ministry of Defence’s involvement in weather modification experiments, to which the Met Office responded, revealing mountains of information.
RAF’s First Rainmaking Experiment: Cloud Seeding with Dry Ice Over England in 1949
Historical records reveal that the UK's first experiments in rain generation through cloud seeding with solid carbon dioxide (dry ice) took place in 1949 in collaboration with ICI. In August of that year, a Vickers Wellington T10 training aircraft from RAF Middleton St George, piloted by Flight Lieutenant Otley and his RAF crew, conducted three sorties, dispersing 'Drikold' dry ice provided by ICI into clouds over the North-East of England and the North Sea.
The Origin of Project Cumulus Observing Weather with Gliders, Amid Speculation of Independent Cloud Seeding Trials
The "Project Cumulus" experiments were primarily designed to study meteorological conditions rather than actively generate rainfall. Observations were carried out using ground stations and a modified T-21 glider operated by the Imperial College Gliding Club. However, there is evidence suggesting that cloud seeding might have been conducted by the Imperial College team at Cranfield as part of a trial separate from the Met Office’s oversight.
MPs Pushed RAF to Deploy Silver Iodide Cloud Seeding Amid Expert Warnings Against Large-Scale Trials
In December 1955, Members of Parliament from drought-stricken constituencies urged the RAF to expand cloud seeding efforts to mitigate the severe water shortage. In response, the Under Secretary of State for Air instructed that ground-based cloud seeding using silver iodide generators be conducted at a suitable location in the Pennines, following the model of the ongoing experiment on Salisbury Plain.
Mainstream Press including The Guardian, The Telegraph and The Daily Mail reported unearthed documents in August 2001.
The media reported on uncovered documents and interviewed a pilot named Alan Yates, who worked on Operation Cumulus at the time. He flew over Bedfordshire, spraying salt, which resulted in a heavy downpour over Staines in Middlesex.
Met Office and MRF Cloud Seeding Experiments Documented in Scientific Journals, 1940s–1980
This draft highlights notes on the MRF/Met Office’s involvement in cloud seeding experiments from the late 1940s to the 1980s, covering research flights, Meteorological Office discussions, the deposition of dry ice and silver iodide, and ‘new methods of stimulating convective clouds to produce rain and hail.’
Declassified Air Ministry Meteorological Research Committee Report from 27th February 1954 — examining the role of ice crystals, artificial rainmaking, and cloud seeding methods like silver iodide and dry ice.
Declassified report reveals the Air Ministry Meteorological Research Committee’s findings on artificial rainmaking and cloud seeding techniques, including the use of silver iodide and dry ice.
The Met Office’s Role in Cloud Seeding Experiments Published December 2002
This text explores the Met Office’s involvement in cloud seeding experiments from the late 1940s to the 1950s, focusing on the loss of key records and the shift from weather modification to cloud process studies. It addresses controversies, such as the BBC’s 2001 link between Met Office experiments and the Lynmouth flood, and the challenges of accurately documenting these activities. The study aims to fill historical gaps and offer a clearer understanding of the Met Office’s role in early weather modification research.
View the 262 pages of declassified documents here.