LIGHTNING AND THUNDER
What is lightning? Lightning refers to one of the several forms of visible electrical discharge produced by thunderstorms. The primary forms of lightning discharges are cloud-to-ground (CG), cloud-to-cloud (CC), in-cloud (IC) and cloud-to-air (CA). Rare forms also include ball lightning. Lightning appears very bright because it is - its optical output is equivalent to some 100 million light bulbs going on and off.
Why does lightning appear to flicker? Does lightning strike twice - yes, in fact often many more times than twice. When you see a flash of lightning, it often appears to flicker. If you were to video tape that flash, on slow play back you would find that many flashes are composed of multiple successive strokes, which most of the time follow the exact same path as the initial stroke. Thus flashes are composed of strokes, typically several in number. The actual stroke lasts on the order of millionths of a second, separated in time by several tens of millisecond (thousands of a second). The entire flash can some times last for a quarter second or more. Some flash have a very large number of strokes, with the worlds record thought to be 47 in a single flash.
Does lightning strike up or down? It goes both ways. Lightning is a giant spark, but it occurs in a rather complex manner. There is often an initial breakdown within the cloud. Then a faintly luminous stepped leader emerges from the cloud and progresses a series of jagged motions towards earth at an average speed of around 200.000 mile per hour. As the stepped leader approaches the ground, an upward streamer emerges from the object about to be struck. When the two meet, this completes the path to ground, and the cloud is short-circuited with a brilliant, luminous 60,000 mile per second return stroke from the earth to the cloud. If the flash has more than one stroke, a dart leader emerges from the cloud and follows the same path to ground without branching, and as it approaches the object to be hit, another upward streamer emerges, resulting in the next return stroke. Occasionally the stepped leader originates at the ground (more l;likely from a tall building or tower), and moves upwards. The branching of the first stroke would then look like an upside down tree. This could also be considered true "upside down lightning".
Are there two kinds of cloud-to-ground flashes? There are basically two distinct types of CG flashes, as they are often called, negative CGs and positive CGs, though they generally look the same to the naked eye. The negative CG is by the most common (perhaps 95% of the total) lower negative charge to the ground. The less common positive CGs then lower positive electrical charge to the ground. The positive CGs typically have stronger peak currents, are less likely to have multiple strokes in a flash, and often have a continuing current, which lasting many tens of milliseconds, allow the struck object to be intensely heating and causing ignition. The positives CGs are thought to be the chief forest fire starters.
What is thunder? The angels bowling? No. Thunder is the sound emitted as a result of the rapidly expanding gases along the rapidly heated lightning channel. When lightning strikes very close, one sometimes hears a tearing sound,. This is believed produced by the stepped leader which precedes the first stroke in a flash. The sharp crack head at very close range, just prior to the main thunder crash, is caused by a ground streamer ascending to meet the stepped leader of the first stroke.
Can you have thunder without lightning? Can't be done, if only by definition. But you might not always be able to see the parent lightning discharge. Especially during the daytime, lightning discharges deep within a cloud are difficult to see. And more than 80% of all lightning discharges are with clouds.
How hot is lightning? Some like it hot - and lightning is just for them. The air the core of a lightning bolt had been estimated to be heated to as much as 54,000 degrees F. That happens to be about six times hotter than the surface of the sun.
What are the electrical currents within lightning discharge? They are highly variable. The average lightning stroke has a peak current on the order of 30,000 amps. But some discharges, especially those that are totally with in the cloud, are only several thousand amps. On the other hand, superbolts do occur, occasionally reaching 300,000 amps of more. The electrical potentials involved in lightning discharges can ranged up to 200 million volts.
How often does lightning occur on our planet in a year? There are probably 1500 to 2000 thunderstorms active around the world at any one time. It has been estimated that lightning flashes approximately 100-125 times per minute on a global basis. Lightning therefore flashes approximately three billions times each year across the whole planet.
Can you survive a lightning strike? Yes in fact the majority of the people struck do not die, Estimates of the mortality rate from lightning strikes range from 5% to 30%. But your odds of survival are significantly enhanced if you are stuck on the presence of someone who knows CPR. The basic rule to follow if several people are struck by lightning is to "save the dead first". Often lightning victims appear dead but are in fact in cardiac arrest. The immediate application of CPR can bring them back to life. More often than not people who have been struck and are screaming and howling, while obviously in pain, are usually in less imminent medical danger. Many people think that someone who has been struck by lightning are still somehow electrically charged. This is nonsense. There is no danger whatsoever in touching a lightning strike victim. More people are killed by lightning every year than by rattlesnake bites. Moreover, you have less than 3 chances in a 100 of actually dying from a rattler bite. Las Vegas wouldn't give you those kind of odds for surviving a lightning hit.
Can you survive a lightning strike more than once? Some people like to push to odds. And at least one person has been hit by lightning some seven times and survived. An American park ranger by the name of Roy Sullivan was nailed sever times between 1942 and 1977. Known as the "human lightning rod", Mr. Sullivan survived being struck, although his hair was set on fire twice and he suffered burns on various parts of his body. But he lived. Kids, he is a professional. Don't try that at home. Though lightning is hot, the discharge usually lasts such a short time that serious burns do not necessarily occur. And current usually prefers to stay on the outside of an object. Unless the discharge goes through the heart or spinal column, a victim can often survive.
Do lightning strike victims burst into flame? In spite of the Saturday morning cartoon depictions, those struck by lightning do not become crispy critters. Some of their clothing may be singed and smoking and they may have burn marked, but flames, no.
What is a fulgerite? OK, you're digging out in the back yard garden. You strike something hard. You keep digging...and unearth a 15 foot long, hard lumpy tubular "thing" that is white/green/gray in color. Quiz: What have you found? (1) Part of a UFO (2) A giant dinosaur leg bone? (3) fossilized lightning. Number 3 is the winner. Called a "fulgerite" it forms when a powerful lightning bolt melts the soil into a glass-like state. Such a record large specimen was found several years ago in Michigan. Visitors to the Great Sand Dunes National Park in Colorado get to see example of fulgerites extracted from the/ he nearby sand mountains. And in order to make point to the many hikers who take off for a days stroll through the dunes, the last sign they see warns them to take cover in thunderstorms and not to become fulgerites.
How safe are you from lightning inside an airplane? Commercial airliners are generally quite safe during electrical storms. A commercial airliner is on the average struck by lightning twice per year. Not to worryÑthe metal skin of the plane conducts the current on the outside like a Faraday cage. Fuel tanks are now designed to prevent entry of electrical charges. The last major U.S. commercial airliner crash caused by lightning was more than 35 years ago. Flying through a thunderstorm can be a bouncy and sometimes unnerving experience. But while the up- and downdrafts can be a potential hazard, you at least don't have top worry much about lightning. If struck by a bolt, the current is largely directed around the outside of the aircraft's metallic skin. Passengers might see a flash, hear a bang, but as for a shock, or worse, not to worry. Since today's commercial airliners are well protected from lightning strikes, a direct strike usually causes little or no problems. Usually. On August 4, 1992, a DC10 flying from Denver to Minneapolis flew into a thunderstorm. It took a direct hit. In addition to burned out electronics, some of the rivets on the fuselage were damaged. The plane landed safely but mechanics had a lot of work to do. A commercial airliner is usually a pretty safe place to be during a lightning storm, especially when parked on the jetway. On 21 February,1995, a lightning bolt struck an MD-80 aircraft as it was departing the ramp in Phoenix. None of the 131 passengers on board were fazed, but three airline workers outside were injured seriously enough to require hospitalization. The plane made its scheduled trip to Chicago without incident. The worst lightning related aviation disaster occurred over Elkton, MD on 8 December 1963. Lightning struck and penetrated the reserve fuel tank, igniting the vapors and sending the plane in a fiery crash, killing 82 persons. This tragedy results in numerous design changes in aircraft to prevent its repetition.
How safe are you from lightning inside your car? You are generally safe from lightning while inside a car, the rubber tires providing some shielding, with the metal body proving a path way for the current to flow being the main factor. Being struck in a vehicle can be an experience though. Lightning struck and severely damaged a pickup truck in Blue Earth County, Minnesota on 7 August 1994. The occupants inside? No problem. A motor vehicle is actually a very safe and well insulated place to be during a lightning storm. A car traveling on I-35 near Des Moines, IA was struck directly by a bolt of lightning. The car stopped dead in its tracks, but the startled driver was none the worse for wear. The car had major electrical damage, many small holes in its body, and all four tires eventually went flat. The roadway beneath the car had a yard wide, several inch deep crater. The driver's first name was Rod and the most enduring effect of the incident is that his friends now insist in calling him Lightning Rod. It was just one of those days when two Michigan motorists had an accident during a rainstorm. While huddling under an umbrella watching the tow truck hoist their wrecked car, lightning struck the umbrella, zapped the motorists, and then jumped over and shocked the tow truck driver. None were seriously hurt, but they were not in a good mood by day's end. We note that a car is a very dangerous place to be during a tornado. Standing under a tree is a bad idea during both a tornado and a lightning storm.
How safe are you from lightning inside your home? Being inside a building during a lightning storm is generally quite safe. Of course you don't want to be talking on the phone (cordless or cellular excepted), holding into plumbing fixtures, of working with electrical appliances. And there are some exceptions. A lightning bolt struck a house in Denmark, went down the chimney, knocking plaster off the living room walls, ripping curtains to shreds, and smashing a clock to bits...while leaving a caged canary inches away unfazed....then breaking 60 window panes and all mirrors, blasting through the door into the back yard, killing a cat and a pig before burrowing into the earth. Lightning can do weird things. A house in Iowa was severely damaged by a lightning bolt. A pile of twelve dinner plates was found to have every other one broken. On 24 October 1991, one resident of Chicago Heights, IL was comfortably sleeping in bed when....KABOOM. Lightning struck, traveled through a cable television line into the house, struck the bed, which then caught fire. The person was treated for shock (not the electrical kind). Was this dumb luck or Devine Intervention? A 75 year old German grandmother was being attacked by a street burglar. As the assailant raised a crowbar with which to strike her, he in turn was struck dead by a bolt of lightning. The woman notes her attendance at Church has become more frequent since the incident. We will let the reader decide for his or herself the theological implications of the incident.
Is lightning a sign from God? We'll continue to avoid theological discourse, but we do note that many cultures have believed this. Ancient Romans saw Jove's thunderbolts as a sign of condemnation and denied burial rites to those killed by lightning. Some cultures have made medicines from stones struck by lightning., Roman, Hindu and Mayan cultures all held the belief that mushrooms arise from spots where lightning has hit the ground. In ancient Greek mythology, Zeus was the great bearer of rain, thunder and lightning. Spots struck by lightning were frequently fenced in by Athenians and consecrated to Zeus.
Does lightning every do any good? Well, its very pretty and makes for some really neat pictures. It also fixes the nitrogen in the air which is used by plants. And every once in while it does some good deeds. According to an article published in Scientific American in 1856, an intense lightning discharge hit the ground in Kensington, N.H. and made a hole about a foot wide and 30 feet deep, forming a well which soon filled with good water. A Greenwood, SC man (by profession an electrician) survived a direct strike by lightning 28 years ago. But since then he has never been cold. He can stay outside in sub-zero temperatures wearing summer clothing for hours without discomfort. About 600 people per year are injured by lightning, and sometimes (albeit rarely) come out aheadÑthere are several stories of blind people regaining their sight after a tangle with a bolt. Talk about shock treatments! It is reported that lightning once struck a house in Minnesota, setting it afire. But this bolt must have had a conscience, as it then leaped across the street, striking a fire alarm box. The power surge resulted in an alarm being sounded, and the fire department responded promptly and put out the house fire. A woman living in Kansas was once talking on the phone with her husband (who had called to find out if she was OK during a storm) when the line was zapped. She was knocked unconscious, and ever since has been absolutely unable to tolerate any alcoholic beverages. There is a published claim of improved intelligence on psychological testing after a lightning strike. A woman in southern Illinois claims to have become psychic after being zapped. She claims to help police agencies in locating missing persons. An then there was a gentlemen who believed he had become "hypersexual" after his lightning injury because he could not get enough sex. (Do I see the potential for a new health fad here.....)
If a lightning flash takes only a fraction of a second, how come thunder lasts so long? While we see the flash virtually instantaneously, the beginning and end points might be 5 or more miles separated. Due to the slower speed of sound, it takes differing lengths of time for the shock wave to reach our ears. If the lightning channel was two miles long, and assuming it started directly overhead, it would take at least 10 seconds for the rumbling to stop.
How many people are killed and injured by lightning each year? When people say the chances are the same as being struck by lightning to described a low probability event, they had better go check their figures. Over 7000 Americans have been killed by lightning in a recent 34 year period. Your chances of being struck by lightning in the U.S. are about 1 in 250,000 and 400,000. You can increase your odds, if you would like, by golfing, swimming, boating and just being outside during a thunderstorm. In the U.S. alone each year, between 75 and 150 people are reported killed by lightning with 5 to 30 times that being injured. And these statistics are thought to be underestimates of lightning casualties. It is possible many lightning victims cause of death is listed as burns or cardiac problems. The deadliest month for lightning fatalities and injuries in the US is July. The large number of thunderstorms combined with numerous vacation trips and other outdoor activities yields this deadly total.
Can there be lightning during a snowstorm? Lightning is usually associated with thunderstorms, and therefore is thought to be a spring and summer event. Yet lightning does occur during winter, and even during heavy snowfalls and blizzards. Winter lightning appears to be unusually powerful, associated with loud and long thunderclaps. Sometimes associated snowfalls can reach 3 inches an hour. A man was struck by lightning during a blizzard in Minneapolis during March of 1996. He is still alive...and very puzzled.
What is the fair weather electric field? If you had a fancy "volt meter", you could demonstrate that even in the fairest of weather the atmosphere has a potential gradient. Near the ground the electric potential in air is roughly 100 volts per meter in the vertical. The total potential through the entire depth of the atmosphere is around 300,000 volts.
Are thunderstorms the only source of lightning? Lightning is usually associated with thunderstorms. On a few occasions, lightning has been observed within giant steam and debris clouds from erupting volcanoes. Lightning, and even miniature tornado-like vortices attended the spectacular volcanic birth of the island Surtsey near Iceland. Giant plumes of smoke from large forest fires also have been known to produce lightning, although these smoke clouds were probably in the/ he process of turning into regular thunderstorms. In the western US, most forest fires are started by lightning. Sometimes the heat from the intense fires trigger new thunderstorms ... which in turn can produce more lightning. This is called a feedback loop.
Can lightning strike twice? In many ways. As mentioned, in a typical lightning flash, often several strokes hit the same spot in rapid succession. Tall structures and buildings such as the Empire State Building in New York City, the Hancock Building in Chicago and the CN Tower in Toronto are hit many times each year. This fact has actually led to conducting research sites in lightning in using structure like these. In general any object struck by lightning is generally a better candidate to be struck again than something which hasn't been zapped. And then lightning does strike twice...and sometimes with apparent malevolence. On 8 August 1937, three persons were killed by a bolt that struck Jacob Riis Park beach in New York. On 7 August 1938, almost a year to the day later, lightning again struck the same beach, and again killed 3 bathers. Don't tell a homeowner in Arvada, CO that lightning doesn't strike twice. His new house was struck during a summer thunderstorm and sustained considerable damage. Just as they were getting things back in shape six weeks later- shazaam! and $30,000 more in fire damage.
Can you make lightning indoors? Easy, although on a rather small scale. When the indoor relative humidity is very low, which it often is during winter, static electricity builds up on your shoes and clothing can generate notable electrical discharges. It can result in "that annoying static cling" on your dress, and a lot more. In fact, each inch of spark represents a potential difference of 40,000 volts. So a three inch discharge represents a 120,000 volt potential difference. This is why you want to protect your PC from static electricity. Cat fur gives up its electrons easily. So if you need to generate an electrical spark .... just grab that kitty and rub away. Does lightning give off radiation besides light? In 1895, William Roentgen discovered X-rays. Much more recently atmospheric scientists were surprised to find that thunderstorms can produce X-rays during lightning discharges. Of course lightning also radiates radio energy over a broad range of frequencies. Some of this energy is with the AM broadcast band, which produces the familiar static heard on many summer afternoons and evenings. Another name for this static is sferics, short for atmospherics.
Where does lightning like to strike? Lightning strikes most portions of the globe sooner or later, but it does have its favorite haunts. Weather satellites suggest that the vast majority of lightning strikes to the planet occur over land areas, even though it comprises only about a quarter of the earthÕs surface. Not too surprisingly, the tropics receive two thirds of the lightning bolts. But some mid-latitude storms, such as those which room the interior of the U.S, during summer night time hour, can be prodigious producers of lightning.
What sporting activities are prone to lightning danger? Virtually anything you do outside during spring and summer involves a lightning risk. Swimming, boating, hiking, golfing, soccer...if you are out there, you are a target. Most lightning deaths in the U.S. (in descending order) occur (1) in open fields or ball fields, (2) under trees, (3) while boating and fishing, (4) near tractors and heavy equipment, (5) on golf courses, (6) and on telephones (but not cellular or cordless ones). A young man fishing in Indiana in 1993 caught more than he was planning on. While carrying a fishing rod over his shoulder as he walked away from a pond, it was struck by lightning. He was hospitalized but did recover. Wonder what his bait was. Perhaps Frisbee is joining golf as a dangerous sport? During a Frisbee match in Nashville TN on 10 April 1994, lightning struck. One person was killed and 18 were injured. The safety rules are the same for all outdoor activities. If lightning threatens, get inside - and don't seek shelter under trees. Golfers are generally not significantly more often struck by lightning than most outdoors types, but their are plenty of golf-lightning tales. Golfers Lee Trevino and Jerry Heard were both struck by lightning during the 1975 Western Open in Chicago. Both recovered after hospitalization. Over the years, hundreds of other golfers who failed to leave the course after lightning was spotted have been far less fortunate in their encounters. Thor showed his wrath in the land of Vikings in June, 1991. On 13 June one spectator was killed and 5 others injured while taking shelter under a tree during the US Open Gold Tournament near Minneapolis. Then on 29 June, four were injured when lightning struck nearby at a St. Paul golf course. While the lightning fatality at the 1991 US Open made headlines, 37 year old man was killed by a bolt while golfing near Louisville, KY. Two others were injured. All were standing under a cluster of trees.....The rule still stands...don't stand (or sit) under a tree during a thunderstorm. Get inside. But with all the talk of lightning hits during recreation, those working for a living in outside jobs are equally at risk. Postal employees, construction workers, farmers, and many others need to take care. Five miners were killed in Texas in May of 1985. They were all taking a lunch break while sitting under a 35 foot oak tree. Only the one lightning flash was seen in a classic bolt from the blue scenario. Cowboys and farmers are at risk. Cowboys are a tough breed. One Utah cowboy was literally blown out of his saddle when struck by a lightning bolt in August 1993. He found a hole in his felt hat, his hair was melted in several spots and he had numerous burn marks on his torso. His faithful steed, however, didn't survive. Not everything that happen in an amusement park is funny. Four workers where injured after being struck by a bolt of lightning while they were dismantling a ride in Warrick County, Indiana on 2 September 1991.
Do lightning rods work? Yes. Lightning rods, invented by none other than Ben Franklin, neither attract nor repeal lightning bolts. They do, however, provide a safe path to ground for the flash. Indoor plumbing, which includes pipes buried deep in the ground and vents extending above the roof, have long served as surrogate lightning rods for homes. However with the trend towards using PVC rather than metal pipes, this "free" lightning protection has vanished from many newer homes. But to be effective lightning rods must be properly grounded, and there should be no sharp bends in the cable leading from the air terminal (the pointed rod) to the grounding rod.
And now a word from Smoky the Bear about lightning. Lightning is the leading cause of forest fires in Alaska and the western U.S. In the past decade, over 15,000 lightning-induced fires nationwide have burned over 2 million acres of forest. But stupid campers with their camp fires and nut cases who like to see things burn are still a major cause of burns, especially near large cities. But Smoky would like to find some way to help stamp out lightning.
Does it need to be raining for lightning to strike? It is a myth that if it is not raining there is no danger of being struck by lightning. Bolts can and often do strike as much as ten miles outside of the rain area of the parent storm. Recent research on lightning deaths finds that most fatalities occur in the period when the storm appears to be ending. During the height of most thunderstorms, people are inside seeking protection from the rain. For the ten or more minute period after the rain ends, and even after the sun comes out, lightning is still a threat. People leave their shelters and ....wham! People apparently have enough sense to come in out of the rain, but to get out of the way of lightning. Remember, if you can hear thunder, you are close enough to the storm to be struck by lightning. Move at once to a sturdy building or vehicle.
How close was that lightning bolt you just saw hit the ground? Count the seconds between the flash and the bang, and divide by 5, and you have the answer in miles. Sound travels about one mile in five seconds, so by timing the interval between seeing the lightning and hearing the thunder is a pretty good indicator of how close you were to "ground zero". Thunderstorm approaching. Where to go? A car or truck (with windows closed) or the inside of a building are your best bets. Where not to go? Avoid standing under trees, near fences, railroad tracks, tents, hilltops, golf carts, or holding onto telephones, electrical appliances or plumbing. And stay out of the water! Open sided rain shelters are not particularly good protection from lightning either.
Could we harness the power of lightning? Well, first of all "catching" lightning is not the easiest thing to do. But even if could capture and store a bolt, there is less energy there than you might think. Though very powerful while it last, the typical stroke only last for millionths of a second. If the total energy of a single lightning flash were captured, it would only run an ordinary household light bulb for several months time. Meanwhile lightning is one reason why U.S. electricity bills are not lower - lightning strikes destroy more than $100 million worth of utility power transformers each year.
Could being struck by lightning be genetic? Is it in the genes? A midwest woman was struck by lightning in 1995. Nothing odd there, you say. But her nephew had recently been struck and suffered temporary blindness. Her cousin was dazed in the 1970s when lightning struck her unfolded umbrella. The same woman had been struck once beforeÑin 1965. Her grandfather was killed by lightning on his farm in 1921. And his brother was killed while standing in the doorway of his house in the 1920s. At this rate that part of gene pool will soon exhausted.
What if you are caught outside in a lightning storm? If you are caught outside in a lightning storm and canÕt make the shelter of a car or building, then get away from isolated trees, tall objects and hilltops. [Being deep inside a grove of trees is safer than being exposed in the open.] Do not be the highest point around. Avoid direct contact with other persons (in a group, donÕt hold hands or hug each other!), get into a ditch or shallow depression if possible, crouch down with feet together and with your hands on your knees. Remove metal objects such as belts and golf clubs. And then promise to be more alert to weather signs and not get yourself in such a fix again! Is lightning related to rainfall? Lightning is produced inside thunderstorms as a result of the formation of precipitation particles. For each lightning bolt that hits the ground, on the average about 200,000 pounds of rain are also formed.
Do we understand everything about atmospheric electricity? Based on the following story from the truly weird department, apparently not. In 1991, two young girls near Bristol, England were playing frisbee. Suddenly the disk was hurled back at one of the girls by some unseen force. Then both were enveloped in some sort of "yellow bubble". They received slight electric shocks, were thrown to the ground, and had problems breathing. Eventually they freed themselves from their capture and ran home, quite terrified by their experience.
What is a bolt from the blue? A bolt from the blue. It is more than just a figure of speech. Lightning bolts can on occasion jump 10 or more miles out from their parent cloud and appear to strike in a region having blue skies overhead. Such was the case on this date in 1995, when lightning struck a ball field near Miami, FL, injuring 10 children and a coach. The skies were clear save for a line of clouds to the distant northwest. Is lightning sexist? Lightning seems to be picky about what it hits. Some studies suggest that it preferentially strikes oaks trees over other species. And it certainly is sexist, striking and killing men far more often than women. In Great Britain over a two decade period, 85% of lightning fatalities were men. In a recent study of Florida lightning fatalities, 87% of the persons struck by lightning were males. Before suspecting a plot by radical feminists, note that while 34% of the males struck by lightning were killed, 44% of the females struck died. Take cover immediately..... During severe thunderstorms and tornadoes lashing the Huntsville, AL area in February 1995, National Weather Service staff were on television warning people of the dangerous storm conditions. Just then, the weather office took a direct lightning hit, a fire started, and the weather radar was knocked off the air.
What is ball lightning? Ball lightning is one of nature's most mysterious phenomena. Usually seen during violent thunderstorms, the spheres of glowing light are typically the size of bowling or basketballs. They can last from a few seconds to many minutes. The spheres can simply vanish into thin air but can also pass through windows glass and screens leaving burn marks behind? Not every scientist is convinced the phenomenon even exists. But there are numerous credible reports of "balls" of "fire" floating through the air, often after nearby lightning strikes. They usually do not cause much damage and even seem "playful". They have been known to roll down the aisles of airliners or pass through an open window into a startled resident's bedroom. On 8 June 1972, a hole, 2 inches across, was punched through a window of an empty office in Scotland during a thunderstorm. Since the glass was melted and fused around both the inside and outside of the pane of glass as well as on the circle of glass found on the nearby floor, it is presumed that ball lightning had passed through the window. Even stranger, the office was in the University of Edinburgh's Department of Meteorology. In Wales, on 8 June 1977, a brilliant yellow-green transparent ball bounced down the side of a hillside. It was visible for about 3 seconds but this event appeared to be the size of a bus! In 1996 in Gloucestershire, England ball lightning entered a factory. It traveled along girders and machinery around the building, lightning blue, white and orange and sending off a shower of sparks. The ball then hit a window and disintegrated. The incident lasted only 2 seconds. The only damage was to the companyÕs phone system, and the nerves of the workers.
How often does lightning strike the ground in the US each year? Lightning detection networks suggest that bolts blast the ground some 25 to 30 million times per year. The lightning hot spot of the U.S. is central Florida. Disneyworld could be called Lightning world. In a typical year each square mile of central Florida is struck some ten times. Most parts of the country east of the Rockies have 10 to 50% of that lightning frequency.
How wide is a bolt of lightning? A big lightning bolt striking the ground might look to the eye that it might be hundreds of feet across, but in actuality the current channel is generally not much thicker than a pencil.
How far away from the lightning bolt can you hear the thunder? Generally thunder can not be heard much more than ten miles from its source. In a city where ambient noise levels are high, often thunder is audible only when the lightning strikes a mile or two away.
Does lightning come from ice? As strange as that sounds, lightning, with a temperature hotter than the surface of the sun, only forms in clouds with large quantities of ice. Electric charge is generated during freezing and melting processes in the presence of snow and supercooled water droplets. 20 July. During the summer of 1993, not only were torrential rains pelting the Midwest (resulting in great floods), but for the first time since records began, the national lightning "hot spot" was located in Missouri - not Florida.
Are lightning deaths on the increase? In the United States, lightning deaths per million citizens have declined some 70% since the 1950s, although the number of serious injuries has only dropped slightly. This is probably the result of several factors, including widespread CPR training which can revive lightning victims. But with more and larger outdoor gatherings and concerts taking place, outdoor crowds during summer pose a special hazard - the chance of a major lightning strike disaster. In July 1991, at least 22 people were injured as lightning struck a crowded beach in Potterville, Michigan. None of the victims were in the water.
If you are not hit directly by lightning, are you safe? No. Lighting can travel through the ground for a considerable distance from where its strikes. It can easily enter your body through your feet. Four legged creatures like cows and horses are even worse off because they have four feet which are further apart than ours, which increases the electrical potential difference. If caught in the open during a thunderstorm, seek shelter from lightning - but not under a cow. On 8 June 1993, ten cows were killed by lightning in Trempealeau County, WI. Also lightning might hit a tree nearby, but a phenomenon called side flash can have a streamer jump sideways to a nearby object. There are pictures of one person being hit directly with side flash killer the person standing several feet from them. And you could also be on the telephone telling your friends what a neat thunderstorm you are having -when lightning could strike the phone line and travel into phone, and your head. Several people are killed this way each year.
Does carrying an umbrella increase your chances of being hit by lightning? Probably. But even more risky world be standing next to a boat mast, leaning on a metal fence, sitting on a railroad track (why would you anyway?) or swimming. On 31 August 1991, lightning struck two recreational craft in the Gulf of Mexico off Panama City, FL. The toll: 2 killed and 9 injured. Any time your are exposed in a thunderstorm, particular near a tall attractive object such as a tree or a boat mast, there is a real risk of being struck by lightning.
How long can a lightning discharge be? If it is a "cloud-to-ground" bolt, then travel distance is limited by the distance from the interior of the cloud to the ground, which is rarely more than 10 miles. But cloud-to-cloud or intracloud flashes may reach for a 100 miles or more in rare cases.
A billion dollar lightning strike? In July 1977, a bolt took out a major power line in upstate New York resulting in a massive 24-hour blackout in New York City. The resulting looting losses were estimated at over $1 billion. There was also a surge in the birth rate nine months later. Maternity costs were not tabulated.
Do cities affect lightning? Perhaps. Recent research suggests that lightning frequencies over and downwind of a number of midwestern cities can be 10% - 20% or more higher than surrounding areas.
Can mountain climbing be risky? Yes, and falling isn't the only problem. Between 1980 and 1991, lightning killed (at least) 50 people in Colorado - and of these 20 were killed while climbing or hiking. Mountain hikers should plan their climbs early in the day before the storms start. If caught in a thunderstorm don't stay mounted on horseback. If in a group, spread out. Cars (if you can find one) are a safe haven. Taking shelter under an isolated tree can be deadly, but the cover of a dense forest canopy is relatively safer.
What is keraunophobia? The irrational fear of lightning is known as keraunophobia. The fear of thunder is termed brontophobia. The fear of tornadoes - sounds pretty smart to us.
The most dangerous part of a lightning storm? Near the end. A study of Florida lightning strike casualties found that the largest number occurred just as the storm was ending, not during its most intense part. Seems people were to quick to declare the storm over and wandered outside from their protective shelters to get nailed by the storm's last flashes. Ugly Luck Department: Lightning struck a Waterford, WI barn on July 10, 1992. Inside the barn was 6000 bales of hay. During the 1990s, roast chicken became a staple of fast food restaurants. But in July 1995 in Miller City, OH nature joined the trend when lightning struck a poultry farm and 68,000 chickens were roasted. In 1926, the Navy's largest ammunition depot was located in Lake Denmark, NY. The storage buildings were sturdy, and equipped with lightning rods. On 10 July, lightning struck. BLAM. Depth charges and TNT bombs went off. Sometimes you just can't argue with Mother Nature. On July 2, 1992 in the Chicago area the fireworks started early. Five people were killed by lightning. Then thousands were left in the dark for up to two days due to widespread, storm-caused power outages. Strike 1: Lightning strikes a chemical plant in Texas. Strike 2: The building catches fire. Strike 3: The fire department finds there isnÕt sufficient water available to put out the fire and the place goes up in flames. The summer of 1980 was a rough one for lightning strikes in Ohio. In Wickliffe, OH the entire high school football team was knocked down by a bolt during practice, with one player being injured. Then 26 people were injured in Tuscora Park, OK, with one fatality. And a lone man was struck and killed - while digging a grave in a cemetery. Lightning struck near a house in upstate New York on 17 July 1988. Among the unusual results: the tires on cars parked in the driveway were flat. The hubcaps were blown off. And the home owner's contact lens also popped out of his eye.
What is heat lightning? Heat lightning is not a special form of lightning. It is simply the reflection of regular lightning off atmospheric dust layers from distant thunderstorms below the horizon.
Can you outrace lightning? The electrical breakdown of the atmosphere during a lightning strike takes place at speeds on the order of 100,000 miles per second. You can hide but you can't run from Zeus.
What if you hair stands on end? If you are outside when a thunderstorm is near by and your hair stands on end, or a fishing line literally hangs in the air after casting....that is a sign of dangerously high electrical fields in the atmosphere. Lightning may be about to strike. Seek shelter immediately.
What is triggered lightning? On March 26, 1987, the Air Force launched a rocket from the Kennedy Space Center carrying a communication satellite into low-hanging rain clouds. At 48 seconds after launch, the rocket was "struck" by lightning - apparently triggered by the ionized exhaust plume trailing behind the rocket. The cost: $162 million dollars (which was not insured except by the taxpayers). A similar thing happened to the Apollo moon landing launch vehicle during lift off, although the mission continued with out incident. Scientists also routinely fire small rockets trailing copper wires into electrically charged clouds which often triggers a lightning bolt to strike in a predetermined location. This capability is being used to study the effects of lightning on electrical equipment and materials, as well as conduct atmospheric research.
Can you get paid to be struck by lightning? Some research pilots actually did. Their job was to fly heavily instrumented F106 aircraft through thunderstorms, deliberately trying to be struck by lightning. And they were really good at their job, getting nailed many times. This seemingly odd occupation was pursued to improve aircraft lightning safety features and to develop better forecasting tools for in-route lightning avoidance. Too bad the old TV show "WhatÕs My Line" still isn't on the air. These guys would be shoo ins.
Can you sit under a tree that grows in Brooklyn? Yes, but not during a thunderstorm. On 9 July 1988, one man was killed an ten were injured during a thunderstorm in Prospect Park, Brooklyn, NY, while seeking "shelter" under a tree. Standing under or near a tree during a thunderstorm is truly dangerous. Nationwide, dozens of people are killed and injured each year as a result.
Does thunder make milk go sour? An "old wives tale" says that thunder causes milk to go sour. Neither thunder nor lightning can have that effect. Although, thunderstorm season comes with high and humidity, and if not properly refrigerated, milk will "turn" sooner than usual, thunderstorms or no.
Want to try an electrifying new experience? Take a vacation. Go hiking in the Colorado Rockies. Climb to near the top of a tall peak to admire the view, and stand there during a thunderstorm. A Massachusetts woman did just that in the summer of 1991. She also had the good sense to be struck by a lightning bolt right in the presence of a doctor and a nurse. They revived her stopped heart with cardiopulmonary resuscitation. Somehow this makes bungee jumping seem perfectly tame by comparison. For those less adventurous, heed the signs posted by the Forest Service, which suggests, among other things to do one's mountain climbing early in the day before the afternoon thunder (lightning) storms get going.
How loud is thunder? Sound intensity can be expressed in decibels (sometimes abbreviated dBA). A clap of thunder can typically register about 120 dBA, or ten times louder than a garbage truck, chain saw or pneumatic drill. On the other hand, sitting in front of the speakers at a rock concert can expose you to a continuous 120 dBA, which can seriously harm your hearing,
Things that go boom at the beach? One enduring mystery has been the reports by coastal residents of "water guns", loud thunder-like booms that seem to emanate from somewhere out over the sea. The reports have been made for centuries, so sonic booms seem to be ruled out. Natural gas explosions are one possibility.
What are the Arkansas booms? In the winter of 1983, residents of Hope, Arkansas, home of President Clinton, heard numerous loud booms during a period of cold weather. No explanation ever surfaced. But recently Senator D'Amato has been trying to link them to the Whitewater Affair.
Can you hear meteors? Things that go boom in the night. And the daytime, too. Sonic booms are routinely produced by supersonic jet aircraft. The Space Shuttle also lays down a path of booms as it descends for landing. But nature, not wanting to be upstaged by humans, knows the trick too. Extremely sensitive networks often pick up sonic booms made by meteorites. But there have long been reports of people "hearing" meteors as they sweep across the sky long before any sonic boom could have reach their ears. Dismissed by most scientists, the mystery was recently complicated by reports of observers "hearing" a swishing sound while watching the Space Shuttle begin its descent from orbit over Texas. This was long before the sonic boom arrived. One explanation is that both objects give off electromagnetic waves to which some people are sensitive.
What is the Sausalito hum? New Age types have long discussed the mysterious hum said to be audible (to some) around Taos, NM. However, houseboat residents in trendy Sausalito, CA are highly aggravated by a quite loud and irritating humming noise that is often heard from 8 PM till sunrise from late September through mid-April. Acoustical engineers have been unable to pinpoint the source of the sound. But biologists believe the noise originates from mating habits of the singing toadfish which lives in the bay. Let''s hope the toadfish don't get into rap.
What are Mistpouffers? We don't know. One of the great mysteries of 19th century science. And still unexplained. Mistpouffer? One of the many names given to strange, dull, distant, explosion-like sounds that were heard sporadically along the coasts of Europe and elsewhere, with no apparent cause.