The New Gods of Weather Can Make Rain on Demand—or So They Want You to Believe

It was questionable however overmuch recognition they could take. They had arrived successful Texas close astatine the commencement of the rainy season, and the precipitation that fell earlier the experimentation had been forecast by the US Weather Bureau. As for Powers’ conception that rainfall came aft battles—well, battles tended to commencement successful adust weather, truthful it was lone the earthy rhythm of things that bedewed upwind often followed.

Despite skepticism from superior scientists and ridicule successful parts of the press, the Midland experiments lit the fuse connected fractional a period of rainmaking pseudoscience. The Weather Bureau soon recovered itself successful a moving media conflict to debunk the efforts of the self-styled rainmakers who started operating crossed the country.

The astir celebrated of these was Charles Hatfield, nicknamed either the Moisture Accelerator oregon the Ponzi of the Skies, depending connected whom you asked. Originally a sewing instrumentality salesman from California, helium reinvented himself arsenic a upwind guru and struck dozens of deals with hopeless towns. When helium arrived successful a caller place, he’d physique a bid of woody towers, premix up a concealed blend of 23 cask-aged chemicals, and determination it into vats connected apical of the towers to evaporate into the sky. Hatfield’s methods had the aerial of witchcraft, but helium had a knack for playing the odds. In Los Angeles, helium promised 18 inches of rainfall betwixt mid-December and precocious April, erstwhile humanities rainfall records suggested a 50 percent accidental of that happening anyway.

While these showmen and charlatans were filling their pocketbooks, scientists were dilatory figuring retired what actually made it rain—something called unreality condensation nuclei. Even connected a wide day, the skies are packed with particles, immoderate nary bigger than a atom of pollen oregon a viral strand. “Every unreality droplet successful Earth’s ambiance formed connected a preexisting aerosol particle,” 1 unreality physicist told me. The types of particles alteration by place. In the UAE, they see a analyzable premix of sulfate-rich sands from the godforsaken of the Empty Quarter, brackish spray from the Persian Gulf, chemicals from the lipid refineries that dot the region, and integrated materials from arsenic acold afield arsenic India. Without them determination would beryllium nary clouds astatine all—no rain, nary snow, nary hail.

A batch of raindrops commencement arsenic airborne crystal crystals, which melt arsenic they autumn to earth. But without unreality condensation nuclei, adjacent crystal crystals won’t signifier until the somesthesia dips beneath –40 degrees Fahrenheit. As a result, the ambiance is afloat of pockets of supercooled liquid h2o that’s beneath freezing but hasn’t really turned into ice.

In 1938, a meteorologist successful Germany suggested that seeding these areas of frigid h2o with artificial unreality condensation nuclei mightiness promote the enactment of crystal crystals, which would rapidly turn ample capable to fall, archetypal arsenic snowflakes, past arsenic rain. After the Second World War, American scientists astatine General Electric seized connected the idea. One group, led by chemists Vincent Schaefer and Irving Langmuir, recovered that coagulated c dioxide, besides known arsenic adust ice, would bash the trick. When Schaefer dropped grains of adust crystal into the location freezer he’d been utilizing arsenic a makeshift unreality chamber, helium discovered that h2o readily freezes astir the particles’ crystalline structure. When helium witnessed the effect a week later, Langmuir jotted down 3 words successful his notebook: “Control of Weather.” Within a fewer months, they were dropping dry-ice pellets from planes implicit Mount Greylock successful Western Massachusetts, creating a 3-mile-long streak of crystal and snow.