Those aren't the phantom cannons of Confederate ghosts booming beside the Nissan assembly plant in Canton, Miss., not far from Vicksburg.
It's just Nissan chasing the rain clouds off of its property.
Nissan has discovered a cost-efficient way to keep nasty hailstones from pounding the shiny new surfaces of its vehicles as they sit in marshaling yards awaiting shipment. It blasts the raindrops out of the sky with 20-foot cannons.
Or at least it blasts the hail-forming raindrops out of Nissan's part of the sky. Once chased off the property by sonic shock waves, they remain free to fall wherever they please -- hail or not.
Three years ago, before the Canton plant opened, a hailstorm raked over the vehicles parked outside Nissan's plant in Smyrna, Tenn. Nissan's insurer began questioning the automaker's efforts to prevent hail damage, and Nissan's engineers responded by benchmarking the industry. But they discovered that little was being done by anybody.
Then they happened onto the concept of the hail cannon.
The cannons, which cost $40,000 to $50,000 apiece, look like long medieval horns aimed straight up at the sky. Using acetylene fuel, ignited by a spark plug when Doppler radar warns of hail conditions, they emit blasts that send sound waves spiraling 20,000 feet into the sky. The theory -- not accepted by everyone -- is that moving the water droplets prevents them from freezing into hail.
Farmers in Tibet have begun using the cannons to protect their crops -- a job previously handled by chanting holy men. Michigan apple orchard owner Bernie Swindeman of Deerfield says he installed cannons after four hail storms cost him $1 million apiece in apple damage. A Texas nut farmer uses them, though his neighbors complained that his cannons were controlling the local weather.
Nissan's own neighbors in Mississippi haven't been happy about the cannon fire either.
Jim Pigott, who lives two miles from the plant, says the cannons fired 30 hours nonstop over Memorial Day weekend. "It was like having a boom box in my driveway," he says.
Residents near the $1.4 billion plant petitioned the Madison County Board of Supervisors to make Nissan stop.
The booming from Nissan't two cannons can go off every six seconds if the weather warrants.
Not only that, but Nissan can't take chances with ordinary rain clouds. If they have hail potential, the cannons fire.
They typically are used twice a month, firing for as long as the weather remains threatening.
County officials decided Nissan is not violating any laws, although last week they summoned a Nissan representative to explain what the mysterious cannons actually do.
"We believe it's working," says Mark Swenson, vice president of engineering for Nissan North America Inc. "We've seen evidence of hail falling around us, but not on us, since we installed the systems. I think we're probably even helping some of our neighbors by keeping the hail off of their property." Nissan installed the cannons in December 2003.
Swenson says Nissan would use the cannons elsewhere if it could. It scrapped a plan to install them in Smyrna because the plant there sits near a small airport.
Explains Swenson: "We couldn't be 100 percent certain that the sound waves wouldn't somehow interfere with low-flying aircraft."
But is it science or snake oil?
Research meteorologist Harold Brooks of the National Oceanic & Atmospheric Administration's Severe Storms Laboratory in Norman, Okla., says he is well aware of hail cannons; they have been used in various forms for more than a century. But there is no scientific foundation behind them.
"There's no evidence that they actually do anything," Brooks says. "It may be possible. But if they really do something, they're doing it through some unknown science that we don't know about."
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