Operation Popeye was a top secret government weather modification operation carried out by the US military in Vietnam.
The project was launched in 1967 for covert warfare purposes. Project Popeye was it's precursor experimental research program into cloud-seeding.
As part of Operation Popeye, the US military used WC-130, F4 and A-1E aircraft to inject a silver iodide and lead nuclei agent into the cloud layer above the Ho Chi Minh trail. The intention of Operation Popeye was to alter the weather conditions and increase the mud layer over the trail in order to slow down the enemy.
From 1967 until 1972, the US military continued to disperse the agent into clouds over North Vietnam, Cambodia and South Vietnam. Project Popeye was a success. The monsoon season was successfully extended by between 30 to 40 days.
However, by 1977 the UN General Assembly banned the use of any weather modification system with the potential to cause widespread, long-lasting or extremely severe effects.
Despite the treaty slowing down the progress of weather modification, the act of weather modification and research for military application still continues today.
Melvin Laird, Secretary of Defense at the time, had denied before Congress that any kind of weather modification weapon even existed after the CIA and Henry Kissenger, Secretary of State, had sponsored Project Popeye without his authorization.
[ Image: Betsisman at Pixabay - Public Domain - https://pixabay.com/en/sky-clouds-storm-fickle-weather-1040277/ ]