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by: Victor Boesen |
Lightning
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The thunderbolt, Lucretius wrote, "can crumble towers, destroy buildings, dislodge beams and rafters, fling down the monuments of great men, rob men of life, butcher cattle, and wreak many other forms of mischief.'"Two thousand years after these observations by the Roman poet, the thunderbolt is still working many forms of mischief. In the United States alone, lightning kills six hundred people a year-more than hurricanes do-and injures nearly three times that number.
For the country as a whole the careless camper and smoker must take the blame nine times out of ten when the woods go up in flames. But in the western states, where there is less rain and the trees are mostly pines, lightning is the main enemy of the forest.
There lightning sets off more than nine thousand fires each summer, leaving the woods charred and silent. No animals are seen, no bird song heard. All living things have been killed or driven out, and it will be a human lifetime before things are the same again.
One year in the national forests of Montana and Idaho, 1,488 lightning fires were counted in ten days. There were 335 fires in twenty-four hours, many flaming up from a single thunderstorm.
But lightning needs no fire to kill the trees. Hitting with jolts of ten to twenty thousand amperes-sometimes several hundred thousand, compared to fifteen amperes for the house- hold current-the lightning bolt literally electrocutes the trees. It has been known to kill 160 trees with a single bolt.
Trees which the lightning merely injures, flashing down inside the bark-the path of highest moisture and least resis tance-with heat of 15,000 to 60,000 degrees, soon fall prey to bark beetles. The beetles then go on to attack the healthy trees nearby. Once this happens, the destruction continues a great deal longer than the fire which invited it.
But lightning fire in the woods is no longer being accepted as something no one can do anything about. It may be con trolled long before science finds an answer to the careless camper and smoker.
In the late 1950's, with help from Montana State University, the United States Forest Service laid out a program of research to see what might be done to cut down on lightning fires by using the techniques of weather modification. To start, the Forest Service studied the special thunderstorm reports which they had been getting from a network of fire lookout stations scattered about the forests of the northern Rocky Mountain states. The reports told when and where the thunder storms struck, how long they lasted, and how much rain and lightning they produced.
They learned that thunderstorms with hail produce more than twice as much lightning as storms without hail. The lightning was also more intense and came faster. And the larger the hailstones the more lightning there was.
Forestry men reasoned that if the hail in a cloud were reduced, it ought to follow there would be less lightning from it. And the way to reduce the hail, it had been strongly indi- cated, was to seed the moisture of the cloud into raindrops before it had time to freeze into hailstorms.
The researchers would have liked to learn more about the nature of lightning and thunderclouds, but the fire hazard was so great that they decided to go out and try some seeding experiments at once. There was nothing to lose.
Two years of experimentation seemed to bear them out. On seeding days there was a great deal less lightning than on non-seeding days. But there was better than one chance in four that this would have happened anyway.
In 1965 they got down to business with a three-year pro gram of new seeding experimentation, using heavier doses of silver iodide, dispensed from the air with improved genera tors. They likewise had new instruments to identify the light ning flashes and an improved way of keeping track of what they were doing.
The results of Project Skyfire were hardly open to argument. During thunderstorms seeded with silver iodide, there were 66 percent fewer lightning bolts to the ground, 50 percent fewer cloud-to-cloud flashes, and 54 percent less total light ning. In short, seeding cut the lightning by more than half.
Donald Fuquay, director of Project Skyfire, concluded that seeding of thunderstorms with heavy doses of silver iodide was an effective measure against fire from the clouds.
For the first time man had struck back at the thunderbolt and it had worked. Up to then he had generally been inclined to leave it alone. The blinding flash and the awesome crash of sound, along, with the terrifying power and mystery, had kept him intimidated.
Since he could not account for this fearful fire and can- nonading from above, man in early times turned to the super natural for an explanation. Thunderbolts, he decided, were weapons in the hands of the gods, who threw them at offenders. Apparently there were enough offenders among the Romans that it took two gods to deal with them. Jupiter hurled thunder bolts by day, Summanus at night.
Throughout the world thunder and lightning were the means by which the gods made their presence known. Among the Greeks and Romans places struck by lightning were set aside as sacred. Anyone killed by lightning was buried on the spot where the divine anger had struck rather than given the usual funeral.
Among some peoples of the African Gold Coast fires started by lightning are allowed to burn, and persons hit by lightning are given no help so as not to interfere with divine will.
Some of the acts once believed to be punished by lightning were lying under oath and desecrating sacred places like churches and tombs. And a sure way to bring down lightning on one's head was to speak or make any kind of noise during thunder.
The bay tree, aspen, beech, laurel and hawthorn were among a number of trees which were believed to ward off lightning. Other trees were supposed to attract lightning-among them the walnut, locust, oak and ash. "Beware of an oak, it draws the stroke; avoid an ash, it courts the flash," said an old verse.
Quaint beliefs and folklore still persist in regard to light ning. In the United States, as well as Germany and France, some people believe that only milk can put out a fire caused by lightning. Another supposition: wood from trees struck down by lightning should not be used as a fuel but can be used for medicine.
The Bible and other such religious objects help to diminish lightning, some believe. Bells, candles, and salt are said to have the same moderating effect. Safety measures against lightning inside a house include staying away from mirrors, windows, and chimneys. The safest place in the house is a feather bed.
The crash of thunder has stimulated people's imaginations in various ways. The Scandinavians believed what they heard was Thor, the god of thunder, throwing his hammer at giants.
Some believed it was God wrestling the Devil to the ground. American Indians heard it as the great thunderbird flapping its wings. In the folklore of certain rural areas in the United States thunder was caused by God rolling his water barrel across the floor of heaven.
Not until Benjamin Franklin did anyone know what light- ning is. Franklin believed it was electricity, and experimented with a kite during a thunderstorm to prove he was right.
Franklin was lucky to have survived the kite-flying episode to write the eighty-page book about his many other experi- ments with electricity which made him famous. Others who tried the experiment with the kite were killed, tragically confirming the deadliness of lightning.
Not only are thunder and lightning impressive to hear and see, but there is a great deal of it. Worldwide, there are esti mated to be some 2,000 thunderstorms going on all the time, hurting thunderbolts at the rate of 100 to 150 a second. That is eight to twelve million thunderbolts a day.
Lightning strikes almost anywhere, but more frequently in some places than in others. In the space of one year, as re ported by the Federal Aviation Administration, lightning struck airplanes in flight one thousand times. Four airliners once were hit in a single day near Los Angeles. Another air liner, flying a holding pattern over Chicago, was struck by lightning five times in twenty minutes.
Fortunately, aside from scaring the passengers, lightning hitting an airplane usually does little harm. Small holes in the skin of the plane, pitting, and scorching are about all that happens. But there is always the danger that the controls may be damaged, causing the plane to go down, or the fuel tanks set afire. This has been blamed for two airliner disasters. Lightning has been known to strike bare, flat ground once in a hundred years or so. Generally it favors high points- trees, buildings, towers-picking the tallest mark because it is the most convenient.
It's mere folklore that lightning never strikes .twice in the same place. For instance, it hits the Empire State Building in New York City on an average of twenty-three times a year. One year it was a record forty-eight times. And once the Empire State stood off eight thunderbolts in twenty- four minutes. The same happens to any very tall structure. At Champagne, Illinois, a television mast nearly 1,000 feet tall shivers to the punch of lightning more than one hundred times a year.
This, of course, is why in medieval times the ringing of church bells inscribed "I break the lightning" during thunder storms, had the opposite effect from what was intended, tak ing a heavy toll of bell ringers as it struck the towers where they pulled at the ropes. In thirty-three years 103 bell ringers died in lightning hits on 386 European church towers.
When Benjamin Franklin invented the lightning rod, the first scientific attempt to modify the weather, there were many who refused to use his invention, holding back on religious grounds. In France it was argued that the same force which produces lightning was also the one that produced life. The French may have been more right than they knew. Lightning striking the primordial ooze billions of years ago when the world was young, may have produced the compilex molecules with which life began, says Martin A. Uman of the Westinghouse Research Laboratories. These basic molecules of life, Uman notes, have been created in the laboratory by firing electrical discharges into simulations of the ancient ooze.
Whatever it may have had to do with the beginning of Iife and despite the death it causes, lightning striking in wooded areas paradoxically has something to do with keeping Iife going by maintaining balance among living things. "Fire is an essential part of the ecosystem," Donald Fuquay said. "We don't want to stop it altogether-only to take the peak off the fires".