The highly classified program attempted to extend the monsoon season over specific areas of the Ho Chi Minh Trail, to disrupt North Vietnamese military supplies by softening road surfaces and causing landslides.
The chemical weather modification program was conducted from Thailand over Cambodia, Laos, and Vietnam and allegedly sponsored by Secretary of State Henry Kissinger and the CIA without the authorization of then Secretary of Defense Melvin Laird, who had categorically denied to Congress that a program for modification of the weather for use as a tactical weapon even existed.
[1] A report titled Rainmaking in SEASIA outlines use of lead iodide and silver iodide deployed by aircraft in a program that was developed in California at Naval Air Weapons Station China Lake and tested in Okinawa, Guam, the Philippines, Texas, and Florida in a hurricane study program called Project Stormfury.
[7] Reporter Jack Anderson published a story in March 1971 concerning Operation Popeye (though in his column, it was called Intermediary-Compatriot).
The name Operation Popeye (Pop Eye) entered the public space through a brief mention in the Pentagon Papers[8] and a 3 July 1972, article in the New York Times.