Notable U.S. Operations Involving Weather Modification

Operation Popeye (1967–1972)

Objective: To extend the monsoon season and increase rainfall over specific areas in Southeast Asia, particularly over the Ho Chi Minh Trail during the Vietnam War.

Technique: Cloud seeding using silver iodide particles to induce rain and disrupt enemy troop movements and supply lines.

Outcome: Operation Popeye increased rainfall significantly, causing flooding and making roads impassable for enemy forces.

Project Cirrus (1947–1952)

Objective: Early U.S. efforts in cloud seeding. Scientists attempted to modify hurricanes by seeding clouds with dry ice and silver iodide.

Outcome: Initial experiments failed, and there was speculation that the seeding altered the path of Hurricane King, which hit the U.S. coast.

Project Stormfury (1962–1983)

Objective: Attempt to weaken tropical cyclones by seeding them with silver iodide in the hope of reducing their wind speed.

Outcome: The project showed limited success and raised questions about whether it was possible to alter a hurricane’s strength or trajectory.

Project Skywater (1960s–1980s)

Objective: Focused on increasing water supply through weather modification, primarily using cloud seeding to enhance rainfall.

Outcome: Various tests were conducted in the U.S., with mixed results regarding the reliability of cloud seeding as a tool for increasing precipitation.

Project Skyfire (1960s) Objective: Fire prevention by using weather modification to suppress lightning in dry regions, thus reducing wildfires.

Outcome: While some success in reducing lightning strikes was observed, the project was not widely adopted.

Weather Modification Patents and Holders

Below is a list of significant weather modification patents and their associated holders. Many of these patents are related to cloud seeding, ionization, and other methods aimed at altering atmospheric conditions:

Patent: US3613992A

Title: "Weather Modification Method"

Holder: Bernard Vonnegut

Date Issued: 1971

Description: A method for producing precipitation through cloud seeding by dispersing substances such as silver iodide into clouds.

Patent: US3564253A

Title: "System and Method for Irradiating a Cloud Formation"

Holder: J.F. Biondo

Date Issued: 1971

Description: A method for altering cloud formations by radiating them with a laser or other energy source to modify weather patterns.

Patent: US6315213B1

Title: "Method of Modifying Weather"

Holder: John L. St. Clair

Date Issued: 2001

Description: A method for modifying weather using artificial means, such as releasing charged particles to induce precipitation or dissipate clouds.

Patent: US20100224696A1

Title: "Artificial Ionization Method for Weather Modification"

Holder: Franklin R. Pierce

Date Issued: 2010

Description: This invention relates to creating an artificial electrical charge in the atmosphere to enhance or inhibit the formation of rain or storms.

Patent: US3784099A

Title: "Method for Dispelling Fog"

Holder: Louis G. Lawrence

Date Issued: 1974

Description: A system designed to clear fog by dispersing water-absorbing substances into the air to decrease humidity and clear visibility.

Patent: US3899144A

Title: "Apparatus for Altering the Weather"

Holder: Gerald L. Pearson

Date Issued: 1975

Description: A system designed to produce artificial precipitation by releasing specific substances into clouds.

Patent: US3437504A

Title: "Rainmaker Device"

Holder: Thomas B. Nelson

Date Issued: 1969

Description: A device that disperses chemicals into the atmosphere to create artificial rainfall.

Patent: US20080216639A1

Title: "Hurricane and Tornado Control Device"

Holder: Fred E. Boyd

Date Issued: 2008

Description: A method and apparatus for disrupting hurricanes or tornadoes by manipulating temperature and pressure in the storm's path.

Patent: US4274707A

Title: "Weather Modification by Artificial Satellites"

Holder: Stephen Salter

Date Issued: 1981

Description: A system utilizing satellites to modify weather patterns by creating artificial clouds or manipulating atmospheric conditions.

Modern Efforts

While the U.S. government has scaled back direct weather modification projects, private and corporate interests in cloud seeding and geoengineering have continued. Several companies and organizations are exploring weather modification as a tool for managing water resources or mitigating climate change.