THE RESEARCHERS HAD ALREADY DONE FOUR FLIGHTS, earlier in January, before they saw the first hints of what they were looking for. The crew of meteorologists, atmospheric scientists, and students had converged near Idaho's Snake River Basin, a horseshoe-shaped depression between ranges of the Rocky Mountains that is 125 miles at its widest point. Most of the state's famous spuds come from this arable land. Each day that the weather was right—clouds containing the perfect amount of super-cooled moisture at the ideal temperature and altitude— the team flew up into the fluff, dropped silver iodide, and watched to see if they were making more snow than there would've been if they'd stayed home and hung on to their silver.

It's called cloud seeding. And people have been planting little chemical seeds into puffy white masses, hoping to change the weather, for some 70 years. But after all that time, no one knows for sure how well it actually works: when or even if the practice makes more snow fall, or how. That's what the team behind SNOWIE—an acronym for Seeded and Natural Orographic Wintertime clouds: the Idaho Experiment—had come to find out.