17. Operation Popeye was an American plan to lengthen the monsoon season
During the Vietnam War, the United States conducted a highly classified operation to manipulate the weather in Southeast Asia. Vietnam received heavy amounts of rainfall during the monsoon season, which occurs from spring to fall. During that period, US war planners and military observers recognized the decrease in traffic moving supplies to communist troops in South Vietnam. They reasoned extending the monsoon season would weaken the enemy. At the same time, creating even heavier rainfall would wash out roads and bridges, make streams unfordable, and damage crops. The United States government created Operation Popeye (though it had other names throughout its existence) to manipulate the Vietnamese weather.
Over the course of five years, Operation Popeye seeded clouds over Vietnam, Laos, and Cambodia, while the US Air Force, Army, and Central Intelligence Agency denied the program’s existence to Congress and the press. It was revealed to the public through newspapers and confirmed with the publication of the Pentagon Papers. Its effectiveness was limited since the exact length of the monsoon season was variable by nature. When it was revealed in classified Congressional hearings in the 1970s, the legislators were more concerned with its cost than the results it obtained. Popeye led to international treaties – of which the United States was a signatory – which bans the manipulation of weather, as well as other “acts of God” as a weapon of war.
