The Science of Cloud Seeding

In 1946, chemist Vincent Schaefer stood inside a General Electric laboratory in Schenectady, New York, and dropped a handful of dry ice pellets into a supercooled cloud chamber. Within seconds, the chamber erupted with ice crystals — billions of them — swirling and multiplying far beyond what those few pellets should have produced. Schaefer had discovered cloud seeding: the principle that a small, deliberate offering into the atmosphere can trigger a downpour vastly disproportionate to what was given.…