Calgary was pummelled on July 12 by hail the size of golf balls. Bad as it was, some say it could have been worse. Earlier that day, Fargo, N.D.’s Weather Modification Inc. sent “cloud seeding” planes into the skies to try to reduce the size of the hailstones set to slam the city; it sits on the northern periphery of North America’s “hail alley.”
Some scientists believe that when silver iodide is shot into clouds, moisture will fuse around the seed; this encourages rain and hail to fall at a point, says Weather Modification field manager Tom Walton, when hailstones are “pea-sized”—before they can take out windshields and dent car hoods. “It’s hail reduction,” says Walton—“not hail elimination.” Beijing, more famously, used the process to stop rainfall during the 2008 Olympics by inducing rain outside the city. More than 40 countries have tried seeding clouds, mostly to make it rain.
In Alberta, four planes and three staff meteorologists scour a territory from High River to Rocky Mountain House; they run “24/7” from June to September, says Walton—“hail season.” The hail-busting program, unique to Canada, the company says, isn’t funded by taxpayers: a consortium of local insurance companies foots the bill. It hired Weather Modification in 1995, after a devastating hail storm caused $75 million in damages in Alberta. The service costs $2 million a year, says Walton; he figures it cuts losses to insurers by 45 per cent.
But hard data is tough to come by, and whether cloud seeding really works is hotly debated. The U.S. National Research Council has concluded that, although promising, there’s little evidence one way or the other. Still, disciples remain convinced. Alberta’s insurers have renewed the contract for 15 years running.