"The CIA would not say why it had decided to fund the project at
this time, but the US government's apparent interest in altering the climate
isn't new. The first big use of weather modification as a military tactic came
during the Vietnam War, when the Air Force engaged in a cloud seeding program to
try to create rainfall and turn the Ho Chi Minh Trail into muck, and thereby
gain tactical advantage. Between 1962 and 1983, other would-be weather engineers
tried to change the behavior of hurricanes using silver iodide. That effort,
dubbed Project Stormfury, was spearheaded by the Navy and the Commerce Department."