Say you don't live in the tropics, or even in a nicely temperate zone where your garden can reliably sprout tomatoes during a lengthy growing season. Say instead you must eke out fresh produce during a severely truncated summer in a northern location like, for instance, Alberta. The answer to your problem, of course, is a greenhouse. So, you invest a few thousand dollars in an aluminum-and-plastic structure, and before you know it, heirloom tomatoes are spiraling upward, flowering and fruiting and generally promising an abundant harvest.
Then comes July. High summer. One day, a tremendous thunderstorm passes over. Exciting! You love lightning. But then, white bullets fire down from the heavens. Golf balls made of ice. It's hail.
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When you dare to go outside again, your windshield is shattered, your trees have been de-limbed, your beautiful new greenhouse is in tatters and the tomato plants inside it are corpses.
Did you forget that Alberta is in the so-called "Hail Alley"? Your insurance company didn't. If you heard a droning sound before the storm, that was a fleet of planes taking off and flying straight into the gathering thunderclouds. Their mission? To cut the hail down to size through a process called cloud seeding.
Back in 1991, a 30-minute hailstorm caused so much damage in the city of Calgary that insurers ended up forking over $342 million to their customers. Loathe to make a payout like that again, they banded together and hired a North Dakota outfit to do something about it. Weather Modification Inc. (WMI) flies cloud-seeding planes above and below hail-producing clouds, while firing flares full of silver iodide in the hopes of reducing the size of the hailstones [source: Sheremata].
How that works, or at least how they hope it works, gets us closer to the answer we seek. Just how big can hail get?
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