IT BEGINS SIMPLY, quietly. A cumulus cloud ambles northeastward from Mexico, bearing water from the Gulf of California and the Sierra. Along its route it collects more water, wringing the already parched desert dry, liberating moisture from swimming pools, center-pivot sprinklers and irrigation canals. After half a day's march it stumbles into the Mogollon Rim and, too heavy to rise above it, turns southward until it hits the next major barrier, the Santa Catalina Mountains.
As it fills with water, it grows: cumulus cloud becomes cumulus congestus, then cumulonimbus, the towering anvil-head formation that marks a midsummer's skyscape in Tucson.
Strange things are happening within that mixture of rising air and moisture. At the top of the cloud, 30,000 feet in the air, the temperature is 60 degrees below zero. There ice crystals, carrying a positive electrical charge, float and collide. At the much warmer bottom, particles of water, also positively charged, swirl about. Somewhere in the middle lies a zone, at about 10 degrees Fahrenheit, made up of "graupel," ice crystals coated with water and hail that rise and fall with the air currents.
For reasons that atmospheric scientists do not quite understand but are avidly pondering, this graupel has acquired a negative electrical charge somewhere along the way. As it does so, and when, as UA atmospheric-science researcher Martin Murphy says, "other special conditions are met," the action begins. Those "special conditions" include the presence of at least a cubic kilometer of graupel or hail in the cumulonimbus cloud's 10-degree band--enough to cover the University of Arizona campus more than half a mile deep.
Where positively charged ice crystals meet negatively charged graupel, magic occurs. First there comes a flicker, a low-powered leader firing downward in an infinitesimally quick burst, perhaps 20 millionths of a second. It stairsteps downward, forked, streaking several times to the ground at a speed of 460 million feet per second. There a "return stroke"--the flash that we earthbound observers see, and that has yielded the erroneous belief that lightning travels from the ground up--rises to meet it.
The union of upward and downward charges creates an explosion, marked by thunder. That explosion can for an instant create temperatures in excess of 50,000 degrees Fahrenheit, five times hotter than the surface of the sun. Its force can equal 10 Hiroshima-size Atomic Bombs.
The process is altogether mysterious, and the attempt to decipher its workings has engaged generations of scientists. Today, many atmospheric researchers, engaged in studies of use to military and aviation interests, continue to ponder the basic mechanisms of lightning, even as new discoveries and new mysteries arise. Most recently, tipped off by space-shuttle reconnaissance photographs, many of those researchers are looking into the red and blue flashes called "sprites" that particularly intense storms send high into the atmosphere.
But sprites are symptoms, not causes. The big questions remain as they have for millennia: Where does lightning come from? Why does it exist at all?
THE SCIENTISTS HAVE much material to study. At any given moment, some 2,000 thunderstorms are raging across the earth, sending off 100 flashes of lightning per second, 8.6 million a day, so that the earth from space resembles the paparazzi's gallery at an Academy Award party.
Those thunderstorms appear quickly. A cumulus cloud can mushroom into howling fury in only 10 minutes, and just when that might occur is anyone's guess. Chuck Weidman, a professor of atmospheric sciences at UA, explains modestly, "Trying to predict when the first lightning bolt will hit is something we just cannot do. We can say there's a cloud out there that meets all requirements to make lightning, but whether it will produce a storm, and when, we don't know."
Weidman is one of several senior lightning researchers on the faculty of the University of Arizona, where lightning studies have been conducted for half a century; it was here that the noted scientist Leon Salanave did much of the work for his book Lightning and Its Spectrum, a standard reference in any storm chaser's library.
The university's eminence in lightning studies, however, is in some measure serendipitous. Although the recent PBS storm-watcher special Savage Skies devoted much footage to southern Arizona, and although Tucson is crawling with people whose living depends in some measure on the mysterious workings of lightning, this is not an especially productive place to study lightning.
Local promoters need not worry about damage to our reputation as a storm-watching Mecca, however. What draws storm chasers to Tucson, Weidman points out, is that "here it's so dry for most of the year that the lightning channel in a cloud is more visible. The clouds are so high that there's plenty of room to see lightning move between the clouds and the ground. That's why the lightning photographs from out here are so spectacular--plus lightning photographers are good at getting saguaros and mountains in their shots, making Tucson look more interesting than the more productive places, which are usually farmlands and swamps."
As a lightning producer, the sky over Arizona ranks far behind Florida, behind Georgia and Alabama, Kansas and Oklahoma, Colorado and Wyoming.
For all that, lightning is still an important factor in the regional environment, especially because the vast majority of our state's forest fires--and some 10,000 forest fires burn each year in the mountain West--are started by lightning.
If you want to see a king-hell lightning storm, Weidman counsels, go to Disney World, not Tucson. In central Florida, one recent "mesoscale system"--a massive complex of thunderstorms--produced lightning at the astonishing rate of 700 flashes an hour, setting a continental record. Weidman, the author of several scientific papers on lightning, is headed there this summer to study the spectrum of lightning with some gadgetry that would work just fine at home, but there he has the advantage of using a high-tech research facility on a National Guard base far from any towns. From that isolated area, Weidman and his colleagues are able to fire rockets into thunderclouds to trigger lightning, so that it comes crashing down right on top of their monitoring equipment.
"We could do the same thing here, I suppose," he says, "but if we did it on campus we'd bring it down on top of something or someone and do some damage."
Surrounded by computer gear that monitors lightning strikes as they occur across the country, Weidman adds, "Yes, there's more lightning to work with in Florida. But I'm usually too busy watching the equipment to see the really spectacular stuff, like when lightning struck a palm tree right here on campus and set it on fire a couple of years ago."
LIGHTNING IS A killer: The National Weather Service reports that about 87 people on average die each year in the United States from direct or indirect strikes. Other federal sources give more generous estimates; the Federal Emergency Management Agency (FEMA), for instance, reports 150 to 200 deaths annually, with another 750 victims incurring severe injuries. The discrepancies can be attributed to the fact, a recently published insurance-industry study maintains, that lightning death and injury statistics may have been under reported by as much as 50 percent in the last two decades, although why this should be the case is not clear. In any event, another report from Colorado, the state hardest hit by lightning in the West, suggests that lightning-caused injuries requiring hospitalization were under-reported by 42 percent from 1982 to 1989, a particularly active storm period.
By any actuarial measure, lightning is the most dangerous force in nature. (A spike in deaths resulting from post-hurricane flooding has skewed the record for the last two years, but insurance-industry statisticians say that the figures should soon return to normal, giving lightning its numerical supremacy once again.) Wherever you live in the United States, you are twice as likely to die from lightning as from a tornado, hurricane or flood.
The vast majority of lightning victims are men under the age of 35 who have either been working or playing outside between the hours of noon and six in the afternoon. Thirty percent of those victims die. Three-fourths of the survivors suffer long-term injuries, including memory loss, sleep disturbance, chronic numbness, muscle spasms and depression. And many of those survivors die early from burns, cardiac weakness or systemic failure, especially of the kidneys.
Observing the statistics closer to home, Richard Wood, former head of the Tucson National Weather Service Office, remarks, "Pima County leads the state in lightning fatalities and injuries, mostly due simply to the fact that most of our population lives so close to mountains. For that reason, we lead the state in flash floods, too."
Don't take cover just yet. Wood hastens to add that the raw numbers are tiny: Since 1959, only 15 fatalities and 37 injuries have been reported countywide. (Coconino County, with 9 fatalities and 13 injuries, and Cochise County, with five fatalities and 28 injuries, follow Pima.) Those numbers are also random. "In the early days," he says, "we worried mostly about people on horseback. Well, not many people ride horses these days. Most of the people who have been hit recently were just out walking in the street--one was a postman--and who were struck there or while seeking shelter under trees."
The bottom-line reality is this: Your chances are higher of dying by almost any other means--by a stray bullet, an under-cooked cheeseburger or an errant pickup truck--than of dying by lightning.
Take heart, then, and do not unduly fear the impending season of storm.
STILL, LIGHTNING SHOULD scare you, even if just a little bit. And if it does, there are some things you can do to keep out of its path.
The first thing is to trust your senses. If you can hear thunder, then you're at risk of being hit by lightning, so keep your ears open. Remarks Chuck Weidman, "Lightning is almost always closer than you think it is." And, Martin Murphy rejoins, "Lightning will develop from two to five minutes from the time charging is detected within a cloud. It comes up all of a sudden." When storm clouds move in, head in the opposite direction, for once you are within a dozen miles of a thunderstorm, you stand a chance of being hit by lightning from the overhanging anvil cloud.
Another is to recognize, however grudgingly, that some of the stories your mother told you about lightning are true. Of the number of people whom lightning has zapped in the last decades, two or three annually are people who were holding the phone, engaged in pleasant conversation while the bolts rained down around them. Another two or three were people who were showering or doing the dishes. Still another couple were people who were changing channels or adjusting the fine-tuning on the TV--according to FEMA, the most dangerous instrument to be around during a thunderstorm. Stay off the phone, then, and away from water, and turn off the tube.
When a thunderstorm appears, stay well inside, preferably deep within a large building equipped with lightning rods. (Nationally, nearly two-thirds of lightning deaths occur in open fields, under trees, or on open water.) The operative notion is well inside: a 30-year-old Page man, reports a recent number of the Western Journal of Medicine, was standing near a glass patio door, watching a passing storm, when he felt something he reported to be like "crawling ants" on his face. He had been indirectly hit by lightning, but, unaware of the fact, he went off to bed. The next morning he found that he could not close his right eye or control certain other bodily functions, the aftermath of a neurogenic lesion that, fortunately for him, eventually healed.
If you must stay outdoors during a thunderstorm, seek the lowest ground around you--a ditch is ideal--as far away from tall structures and water as you can find. Once there, crouch--do not lie down or touch your head to the ground--in the manner of a Baseball catcher, with your hands on your knees. The idea is to have as little of your body in contact with the ground as possible.
Keep away from heavy mechanical equipment, which, the statistics suggest, acts as a magnet for electricity. If you're with a group of people, fan out; lightning probably doesn't seek out groups deliberately, but it certainly finds them. Wait for a while before venturing outdoors after a storm has passed, to avoid residual lightning.
If you can avoid it, stay out of the sky during thunderstorms. Lightning takes out several small aircraft a year, although only one in Arizona since 1983. Bigger aircraft are far safer, even though the National Lightning Detection Board estimates that commercial planes are hit by lightning once apiece each year. Those planes are engineered to withstand the shock of lightning, but every now and then lightning fells one anyway. The largest single lightning-caused crash was on August 2, 1985, when a Delta Lockheed L-1011 jet crashed while landing at Dallas/Fort Worth. In that crash, 135 people died.
And bear in mind that the saw that "lightning never strikes twice in the same place" is flat-out wrong. Lightning often strikes several times in the same area, and these secondary strikes yield more deaths than the primary ones.
IF YOU TAKE no other precautionary measure during a thunderstorm, stay off the links. A huge percentage of lightning strikes on golf courses, and the medical literature is full of reports of golfers, caddies and cart-jockeys being sizzled out on the fairways. It may be that God has a distaste for golfers, or that lightning finds a perfect home in those tree-lined, watery expanses, but the odds are against those who insist on playing through in an electrical storm.
Tucson may not lead the nation in lightning production, but the city is a major center for both lightning detection and golf. Leon Byerley, a consultant with Lightning Protection Technology, whose early-warning system for golf courses was featured on the PBS special Savage Skies, has much to say about the habits of both lightning and linksters.
"Under the best of circumstances," Byerley remarks, "people won't use their own eyes and ears to know when it's time to come in from a thunderstorm. Golf courses in particular are plagued by this kind of behavior, and that makes sense. If you have golfers putting down $150 to play a game, they'll keep on playing regardless of the weather, and the result is that golf courses all over the country are flooded by lawsuits from bereaved people whose loved ones have been killed by lightning out on the course. Those courses are limiting their liabilities by fulfilling their duty to warn. That's where I come in."
For about $12,000, Byerley's company provides a sensor that can detect lightning within a 30-mile radius, coupled with a siren system that most of his customers program to sound when lightning has approached within five miles of the course. Even then, Byerley notes, that five-mile warning doesn't give golfers much time to seek shelter. Some golf courses are putting lightning-protection devices on open shelters away from the main clubhouse, but, as signs on City of Tucson courses warn, these offer inadequate sanctuary from storms.
Byerley counsels that golfers keep an eye on the sky and get off the course as soon as storm clouds appear nearby. "The thinking is, if we have these kinds of warning systems, we may be able to prevent death or injury. But we can't really make all that much of a difference if the golfers choose not to pay attention to them. One golf course in New Mexico that I've worked with, way up in the mountains where there are always thunderstorms hanging around in the summer, reports that half of the golfers ignore the siren when it blows. Here in Tucson, plenty of golfers keep on playing, too. Without common sense, no early-warning system I can build is going to help much.
"I guess you have to conclude," he says, "that human nature is always going to override technology."
I HAVE BEEN dangerously near lightning only a couple of times in my life: once, as a child, in Kansas, when a lightning bolt killed four fellow Boy Scouts camped a few hundred feet from my bivouac; and once in Greer, Arizona, where a proverbial bolt from the blue shattered a ponderosa pine a couple of hundred feet from where I was standing, coating me with a shower of tiny, sizzling toothpicks.
Those were both exceedingly rare events, neither of them cause for boasting, or even of mention except as curiosities. Yet, for all the fear that lightning induces, few people indeed have seen it up close. Fewer still have felt its wrath. For this story, I was unable to find a single person who had ever been hit by lightning--and, significantly, none of the professional lightning researchers with whom I spoke had ever themselves met a victim either. Says Chuck Weidman, "I've heard survivors' tales, but not at first hand. A lot of people who claim to have been hit by lightning probably weren't. They were probably near lightning when it struck the ground and got a shock, but that's probably about it. Of course, plenty of people have been hit by lightning directly, but they aren't around to talk about it."
Two years ago, the writer Gretel Ehrlich published A Match to the Heart, a book reporting her life after having been struck by lightning on the high plains of Montana. In it, she recalls lying on the ground after the strike, gasping for breath and thinking of "the Buddhist instruction for dying--which position to lie in, which direction to face. Did the 'lion's position' taken by Buddha mean lying on the left or the right?"
We'll have to take Ehrlich on faith--as lightning researchers do not--that this unusually clear thinking really occurred at the time of impact. In the meanwhile, if you hear tell at first hand of someone being struck, write their story down. You will add immeasurably to a scattered and tiny literature, and you may even get a best-selling book out of the bargain.
WE STILL DON'T know enough about lightning," Chuck Weidman says, watching the computer screen in his laboratory as icons of bolts dance along a real-time map of southern Arizona. "There are no hard and fast answers to anything about it. There may never be."
For his part, Weidman hopes for a productive season of storms--assuming, as most area meteorologists now are, that 1996 brings a drought-relieving monsoon to Arizona. Nothing would make him happier. "Out here," he says, "you find that people either love lightning or they hate it. I enjoy it, really, just because of the spectacle. I really love watching a good lightning storm."
"But whether you love it or hate it," he says with a knowing grin, "you have to treat it with respect."
OLD-TIME RANCHERS in particular dreaded the onset of the monsoon season, when lightning filled the Arizona sky, for its advent brought with it the season of destructive cattle stampedes. A reporter for the Safford Arizonian, covering an 1899 roundup in the Sulphur Springs Valley, wrote of one such lightning-induced flight:
I dozed off.... I was still semi-conscious when I heard a roar like a mighty tornado, and jumped up as some one said: "Boys, they are gone!" In less than a minute every man is in his saddle and riding...after the fleeing herd. The lightning play is grand; electricity everywhere. Flames dance along the horse's manes; balls of fire gleam on ear tip, and by its flashes the boys locate the band before them.... Far away in front, above the roar of cattle and thunder, the boys can be heard singing to the maddening herd. As we dash on, the sounds appear to be coming more from the left. They are being pressed around, and soon we see, right in front of the crazed animals, looking like a ghost, in a long white slicker, his old night horse lunging and fighting for his head, rides Henry Gray, singing, hollowing and swearing by turns. By a concerted action the herd is thrown together and the milling begins. Around and around they go, no beginning, no ending. Just a solid mass, storming and moaning as only stampeded cattle can. Orders are passed around to give more room. The riders fall back and the milling ceases. Now it begins to rain. At the first drop the herd turns and begins drifting the storm, the boys all getting in front endeavoring to hold them back. "Boys, if we can hold them until they all get wet, we will have their company until morning," said our straw boss, Nels Wilson. But alas! It was not to be. Something gives them a scare, and here we go. No sooner are the leaders checked than others turn leader and the whole herd goes thundering after them. And thus the night passes away. The rain is over, but the clouds still hang heavy. An owl in a pine tree makes the night more weird by its howls.
Not content to let the facts speak for themselves, area storytellers added tall elements to what were already powerful realities. Thanks to gifted Pinal County boosters, the area between Florence and Casa Grande especially inspired stories about the powers of local lightning, which, they maintained, magnetized saguaro cacti in weird ways. "All the magnetic cactus in this neighborhood are either positive or negative. One attracts; the other repels," wrote a reporter, tongue in cheek, for the Florence Tribune, also in 1899. He continued:
Two tramps passing along the road just above Donneley's a few nights ago took refuge under a bunch of this cactus. One of the men was at once drawn up to and impaled on the sharp blades of the cactus, while its octopus-like arms folded around him crushing him through and into the cactus, where his blood, flesh and bones turned into a pulp very much like ordinary mucilage, which trickled out slowly from the aperture made by the passing in of the man's body. The cactus loses its magnetic power while it is digesting its victim. So we were able to look at this wonderful yet gruesome sight and report these particulars.... The body of the other tramp was repelled by the negative cactus and thrown about one hundred feet distant against a positive magnetic cactus where it underwent a similar process to the one just described. We left the sickening scene with sad hearts and with nothing to identify the victims. After and just before a great storm the attractive or repellent power of the cactus is indescribable. Calves, birds and young colts are attracted, impaled, drawn in and quickly converted by the digestive juices of the cactus into the thick mucilaginous substance just described.
The best local lightning story that I've heard comes, as so many of the best stories do, from UA folklorist Big Jim Griffith, who points out in passing that the 17th-century filigree cross atop San Xavier Mission is a cleverly disguised lightning rod. It seems that the uncle of a friend of his, a cowboy in Chihuahua, was out riding fences one day when lightning blew a leg off his horse. The horse keeled over, of course. So the vaquero held up a slab of white cheese and waited for the next stroke of lightning, which immediately followed. The lightning melted the cheese, which he applied to the horse's leg, gluing it back onto the unfortunate steed's body, and off the two rode to shelter.
"The point of the story," Griffith says, "is not really about lightning. It's about the meltability, elasticity and all-around wonderfulness of Chihuahua cheese."
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