Operation Popeye, a secret weather-modification scheme run by the Air Force during the Vietnam War, was supposed to increase rainfall over the Ho Chi Minh Trail, once again by seeding clouds with silver iodide. An astonishing twenty-six hundred seeding sorties were flown by the 54th Weather Reconnaissance Squadron before Popeye was exposed in The Washington Post and shut down. (A related program—Operation Commando Lava—involved dumping a mix of chemicals on the trail in an effort to destabilize the soil.)
