Clouds with extremely cool water are mixed with man-made ice crystals, such as silver iodide and metaldehyde crystals.

VOA: special.2011.01.11

More recently, the U.S. government project Stormfury attempted for decades to lessen the force of hurricanes by seeding them with silver iodide.

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These pellets, usually made of silver iodide, salts or calcium chloride, are physically dropped via plane or shot into the air via rockets.

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These offices, set up over the past 15 years, deploy artillery, rocket-launchers and aeroplanes to seed clouds with chemicals (usually silver iodide) that encourage droplets to form and fall where needed, or prevent the formation of destructive hailstones.

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