Cloud seeding is the process of inserting chemicals (usually silver iodine) into clouds in order to increase precipitation.

Photograph by Christian Neumann, MyShot
  • On November 13, 1946, snow caused by chemicals “seeded” in clouds over upstate New York fell near Mount Greylock, Massachusetts. Dry ice was dumped into the clouds from an aircraft.
    Since then, governments around the world have used cloud seeding for both military and civilian purposes. From 1967 until 1972, the United States military conducted Operation Popeye, which seeded clouds in Vietnam with silver iodide. This had the effect of extending the monsoon season by a month, making supply trails in North Vietnam muddy and difficult to travel. After the Chernobyl nuclear disaster, Soviet military pilots seeded clouds to cause rain over Belarus, which would remove radioactive particles from clouds heading toward Moscow. Austria uses cloud seeding to prevent hail formation during rainstorms. In China and Australia, cloud seeding is used to increase rainfall in areas experiencing drought.
  • Term Part of Speech Definition Encyclopedic Entry
    civilian Noun

    person who is not in the military.

    cloud Noun

    visible mass of tiny water droplets or ice crystals in Earth's atmosphere.

    Encyclopedic Entry: cloud
    cloud seeding Noun

    process of adding chemical material to clouds in order to make it rain or otherwise control precipitation.

    drought Noun

    period of greatly reduced precipitation.

    Encyclopedic Entry: drought
    dry ice Noun

    frozen form of carbon dioxide.

    government Noun

    system or order of a nation, state, or other political unit.

    military Noun

    armed forces.

    monsoon Noun

    seasonal change in the direction of the prevailing winds of a region. Monsoon usually refers to the winds of the Indian Ocean and South Asia, which often bring heavy rains.

    Encyclopedic Entry: monsoon
    radioactive Adjective

    having unstable atomic nuclei and emitting subatomic particles and radiation.

    rain Noun

    liquid precipitation.

    Encyclopedic Entry: rain
    snow Noun

    precipitation made of ice crystals.

    travel Noun

    movement from one place to another.