Sidebar by Ed Quillen
Cloud-seeding – April 2004 – Colorado Central Magazine
If you can make snow fall by shooting particles into the sky, can you prevent hail from falling by dispersing particles?
Hailstones, like snowflakes, begin as tiny particles that attract water in clouds. The difference is that snowflakes fall quickly, whereas hailstones get pushed up and down inside the cloud by air currents, gaining layers of ice until they’re so heavy that they fall and pummel the earth.
So a Canadian company theorizes that dispersing the particles could prevent a hailstorm from damaging field crops, and has built the Hail Suppression System.
It has a built-in radar to detect hail-forming conditions in overhead clouds. When it senses that hail is imminent, it fires a powerful sound wave upwards to disperse the particles in the cloud.
In essence, it’s a cannon that just makes noise, and it’s a bigger version of the carbide cannons that used to be sold as novelties. If you toss calcium carbide into water, it gives off acetylene gas, which will explode under the right circumstances, and can be used for welding under other circumstances.
World-wide, there are about 400 hail-suppression cannons in use, with nine in the United States.
The 120-decibel noise can be heard 5 miles away, and it fires every 5.5 seconds when it’s in action. That explains why these machines are generally used in farming areas, although the Nissan Motor Co. recently installed one at an auto plant in Tennessee to protect new vehicles from hail damage.