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One of the most powerful of all natural phenomena is
lightning. Coming in numerous forms, occurring just about anywhere on the
planet, and able to strike at various speeds and powers, lightning is a force to
be reckoned with. While singularly beautiful, lightning can also be frightening,
loud, and destructive.
What exactly is lightning?
The exact science behind lightning remains a mystery. Basically, meteorologists
and other scientists have determined that lightning is a massive electrostatic
charge that occurs under a variety of conditions, usually thunderstorms, but
sometimes it accompanies volcanic eruptions, heavy snows, dust storms, severe
forest fires, hurricanes and even nuclear detonations.
How nature creates lightning is the unknown factor although a study of the
situations where it is present shows a pattern toward turbulent air. Humidity,
friction, atmospheric pressure, and wind…including solar wind…are all believed
factors in the formation of lightning. Another important ingredient seems to be
ice, which scientists feel forces a separation between oppositely charged ions,
creating a spark.
When charges are driven apart, for whatever reason, it is called electrostatic
induction. This process begins with a powerful updraft that propels water
upwards where it is supercooled and eventually collides with ice crystals
already present, creating a mushy, cold wet substance called graupel. The
collision causes a positive charge to flow into the ice crystals and a negative
charge to transfer to the graupel. As the draft continues to push the lighter
ice crystals upwards, the top of the cloud begins to develop a positive charge
significant enough to be released as lightning.
A similar theory, which encompasses some of the electrostatic debate, involves
polarization. Here, ice crystals or droplets of moisture are polarized as
they fall through the Earth’s natural electric field. When they reach the
updrafts within a cloud, the same general process of electrostatic induction
occur, releasing a bolt of lightning.
The runaway breakdown theory is perhaps more complex, but is also utilized
in several other ideas about lightning initiation. This theory was proposed in
1992 and suggests that cosmic rays ionize atoms, which in turn release
electrons. These electrons make their way through electric fields and in turn
ionize other air molecules, making the air conductive to electricity and
triggering a lightning strike. Leader strokes can move down the cloud in varying
increments (steps) with a very visible charge to follow.
Similar to this theory, is one of mysterious gamma ray emissions triggering
lightning strikes. This theory is under investigation by NASA and currently
many thunderheads are monitored by space shuttles and other observation
mechanisms. This is a perplexing but hot theory in the formation of electricity.
The fact of the matter remains that all theories have some validity, but none
can fully explain how this charge is generated in so many different situations
and in so many different areas of the world. Moreover, there seem to be many
different types of lightning.
Common types of lightning:
The most common lightning stroke actually occurs
within a thunderhead that produces it and most remain unseen by people because
of the thick cloud cover associated with the storm. They appear to be little
more than weak flashes of light silhouetted in the sky. The strokes people are
likely most familiar with are cloud to ground strokes that occur between a
cumulonimbus cloud and the ground. These are usually initiated by a leader
stroke, and are probably the most well known because they are both the most
visible and the most destructive.
Bead lightning is a type of cloud to ground lightning, but it has a
distinctly different look than traditional strikes. As the stroke moves toward
the ground, it appears to split into a series of short and bright bursts. Ribbon
lightning is similar in appearance to bead lightning, but is caused by high
winds that move successive strikes over from the site of each previous stroke,
giving the impression of a moving and flowing ribbon. Staccato and forked
lightning are short but bright blasts that feature a forking pattern.
Dry lightning is a specific type of lightning that occurs without the
presence of a thunderhead or any precipitation at all. This occurs often with
volcanic activity or wildfires when a pyrocumlus cloud is formed from the ash
and debris. While dry lightning is a result of wild fires, it also one of the
leading causes of wild fires, since its strikes occur in areas already very dry.
It creates a vicious cycle of fires that are hazardous and common in areas such
as the American west and the state of Alaska.
The most deadly, while not the most common, type of lightning is positive
lightning, or high voltage lightning. Bearing a positive as opposed
to a negative charge, high voltage lightning can occur out of what appears to be
a benign and clear sky, earning strikes the titles of “bolts from the blue”.
Positive strokes come from the very top of a cloud and travel a long distance,
making them up to ten times stronger than regular cloud to ground lightning.
They also typically last ten times longer, giving them ample opportunity to do
serious damage to anything they contact. While they make up only five percent of
all total strikes, the most damaging and potent strikes are usually positively
charged bolts. One of its dangers comes with its lack of warning. It also
occurs often in winter and other unexpected moments.
Of course, lightning does not need to contact the ground at all. Inter and
intra cloud lightning are both fairly common and occur between two clouds,
or within a single cloud, respectively. This is commonly called heat lightning,
since it seems to occur often on hot summer nights and can be witnessed at
amazing distances while the clouds are lit up in the night sky. It is usually at
such a distance that no thunder can be heard. Thunder, incidentally, always
accompanies lightning. Sometimes, such as in the case of heat lightning, it is
just too far away for the ear to hear, but it is always present.
While all of these are examples of naturally occurring lightning, it is also
possible for lightning to be triggered by the actions of people on the planet or
in the atmosphere. If conditions for an electric charge are simulated or
synthetically produced, a strike of a different nature occurs. For example,
lightning rockets have been launched into thunderheads to induce strikes for
study. These rockets carry spools of wire that unravel and offer a path for the
lightning to follow. Similarly, lightning has been known to strike aircraft when
the phenomenon is desirous of a path. The Apollo 12 was even struck by lightning
shortly after launch. Laser testing and nuclear detonations will do roughly the
same thing and have been known to induce lightning strikes.
How powerful is it?
Lightning is truly a powerful force of nature, whether it is a step leader or
distant intra cloud bolt being studied. While lightning looks to be enormous and
deadly from nearly any distance, most of the size we associate with lightning is
simply illumination. The longest recorded bolt was 180 miles long. The actual
current channel, however, is not much larger than a standard ballpoint pen. This
is a hot and powerful pen. The air within this core of lightning is heated to a
temperature of 54,000 degrees Fahrenheit, about six times hotter than the
surface of the sun. Accompanying these incredible temperatures is a typical
discharge of about 30,000 amps, though intra cloud charges may be only a few
thousand amps. Superbolts from some high voltage positive lightning, however,
have been recorded at an amazing 300,000 amps or more. A standard “C-Cell”
battery is 1.5 volts and homes are typically equipped with power outlets ranging
from 100 to 230 volts. A lightning bolt can carry a charge of up to a billion
volts.
But
is it useful?
As powerful as lightning is, it continues to do more harm than good in the
world. Trying to harvest the power of lightning has been deemed virtually
hopeless by the scientific world. Forcing lightning to go where it is bid is the
first and most obvious problem and many expensive lightning towers would have to
be erected in an area that is frequented by thunderstorms. The other defying
factor is that a lightning strike is so short lived that its rapid burst of
power is over practically before it begins. Rudimentary experiments from the
eighties to present have shown that the energy harvested from an average bolt of
cloud to ground lightning could possibly power a single household light bulb for
several months. Ironically, lightning strikes destroy millions of dollars worth
of electrical transformers each year, creating costly repairs and raising the
expense of electrical power.
Lightning has, however, been reported to have some positive effects. It is
undeniably powerful and beautiful, making it the subject of thousands of
photographs. However, without lightning, scientists believe that the Earth would
lose its natural electric charge very quickly and a dangerous imbalance would
occur. Lightning also electrifies nitrogen so that it is dissolved into water,
creating a rich natural fertilizer for plants, which can only absorb this
necessary nutrient through their roots. Lightning is also a leader in rebuilding
and creating ozone gas, which protects the Earth and its inhabitants from
harmful ultraviolet rays from the sun.
A damaging force
With all of its might, it is a scientific irony that fewer than thirty percent
of all humans struck by lightning actually die. Fewer than five hundred people
are injured annually by lightning strikes within the U.S., about one hundred of
which die. It is the second most common weather related killer of people. It
strikes the ground approximately 25 million times each year in the U.S. alone.
Despite the infrequency of death, it has been enough to inspire numerous adages,
comparisons, and myths.
Strikes on people
Contrary to popular belief, people who are struck by lightning do not explode or
burst into flames. There is often the scent of burned flesh in the air and hair
will typically be singed, but people do not burst into flames. The hottest spots
will likely be any area of the body that touches metal, such as near jewelry or
metal fasteners, like belt buckles. The idea that a body may explode likely
comes from lightning’s effect on sweat. Perspiration on a body is superheated
when the body is struck by lightning, causing instant steam and air expansion.
This may cause frightening phenomena, such as a person’s boots being blown of
his feet or burns to occur in the underarms.
Aside from singing and obvious shock, survivors of lightning strikes report a
range of afflictions ranging from momentary memory loss and blindness to long
term disorders due to nerve damage. Long term memory loss, emotional disorders,
and complete personality changes have all been reported in lightning strike
survivors.
When groups of people are afflicted by a single lightning strike, the adage
“Treat the dead first” has arisen in reference to the appropriate triage
technique. Those with the ability to yell out in pain or are up flailing about
are likely experiencing non-life threatening complications. Those who appear
dead, are likely NOT dead, but rather in cardiac arrest and can be saved with
standard CPR.
There are many other adages concerning lighting and safety. The only one that
seems to ring true is “If you can hear it, fear it.” This saying urges people to
take cover as soon as they can hear thunder. Lightning has been known to strike
up to ten miles away from a parent storm. One that is far more popular but much
less true is “Lightning never strikes the same place twice.” Over the years,
this has been proven completely false. The Empire State Building is struck
dozens of times each year and one man…Roy Sullivan…was struck seven times
between 1942 and 1977.
Where does it strike?
Lightning can and does strike anywhere, but there are plenty of ways to improve
your chances of being struck. The first is simple geographical location. The
state of Florida has the highest frequency of lightning strikes due to the high
surface temperature and very low-lying moist air masses above the surface. This
is true of the entire Gulf Coast area. Areas near the western U.S. mountains
also have a high number of cloud to ground strikes because of the turbulent air.
Still, Florida has twice as many lightning related deaths as any other state.
Singapore and Terasina, Brazil are two other cities with high occurrences of
lightning strikes.
Non-state specific areas that are prone to lightning strikes include the middle
of an open field or ball park. Scientists feel that a lone human standing in a
wide expanse of nothing serves as a type of lightning rod and channels the
electricity to the ground. Heavy machinery, such as that found on modern farms,
serves in a similar fashion with the machinery being both tall and metal.
Isolated structures are also unsafe, but the one of the worst possible shelters
is beneath a tree.
Trees are commonly blown apart by lightning strikes in a manner similar to a
person losing his shoes. The sap within a tree becomes superheated very quickly
and expands, blowing the bark and inner pulp out of the tree. Oak and elm trees
are the two most common types of trees struck, and evergreens follow closely
behind them. What people don’t understand about a tree in a lightning storm is
that they actually make a safe lightning rod to draw lightning from a person if
the person stays AWAY from the tree instead of directly under it.
Being male also seems to add to the chances of being struck. It is unknown if a
chemical makeup accounts for this sexism in lightning, or if the likelihood of
males being in lightning-prone areas (such as near heavy machinery) accounts for
this. Males make up over eighty percent of both fatalities and injuries due to
lightning. Postal workers, farmers, and construction workers are some of the
leading occupations of lightning strike victims. Popular activities that are
commonly associated with lightning include swimming, golfing, fishing, and
walking in an open field. Phone use is the leading cause of death of indoor
lightning fatalities with bathing a close second.
It is recommended that a person seek shelter as soon as thunder can be heard.
Inside a vehicle, while very dangerous during a tornado, is an excellent
insulator against lightning so long as a person does not touch any metal. The
metal of a car will draw the lightning safely to the ground and the tires
provide somewhat of a poor insulator.
Lightning in history
While damaging, lightning has been responsible for some interesting if not
fascinating incidents in recorded history. Its amazing power was recorded by
early Greeks when Zeus was attributed with the ability to throw lightning bolts
from the sky to express his displeasure. Since then, science has been more
involved in the study of lightning, but historical facts still detail its
destructive capabilities.
Some notable lightning disasters from history:
August 1769: A deadly lightning bolt strikes the Church of the Nazaire in
Brescia, Italy. The strike alone was deadly enough without it having ignited
207,000 pounds of gunpowder stored in the vaults. The ensuing blast destroyed
one sixth of the town and killed 3000 people.
July 10, 1926: Lightning strikes the United States Navy’s largest ammunition
depot in Lake Denmark, New York. TNT Bombs and depth charges are released
throughout the depot.
August 8, 1937: Three people are killed by a bolt of lightning that struck New
York’s Jacob Riis Park. On August 7, almost exactly one year later, three more
people were killed when lightning struck the same place.
December 8, 1963: Pan American Flight 214 is struck by lightning over Maryland.
The bolt ignited the reserve fuel tank, causing a fiery crash that killed 82
people. It was the only U.S. airliner ever lost to lightning.
March 26, 1987: Lightning costs the U.S. Airforce 162 million dollars when it
struck and destroyed a rocket carrying a communications satellite just forty-two
seconds after it was launched.
Summer 1988: Forty-two fires started by lightning contributed to the destruction
of nearly forty percent (793,800 acres) of the Yellowstone National Park.
April 10, 1994: One person was killed and eighteen more were injured by
lightning during a competitive Frisbee match in Nashville, Tennessee
October 2002: Hernan Gaviria, famed Colombian soccer star, died after being
struck by lightning during a training session in Cali
October 31, 2005: 68 dairy cows sheltering beneath a tree die from a lightning
strike in New South Wales. Three others recover from temporary paralysis.
Other lightning facts:
- Golfers Lee Trevino and Jerry Heard were both struck by lightning during the
1975 Western Open in Chicago.
- An average American has a 1:700,000 chance to be struck by lightning in his or
her life.
- The Fourth of July has historically been one of the worst
days of the year for deadly lightning strikes.
- Fulgerite is the term for weird root-like particles of sand, fused together
during the heat of a lightning strike.
- Almost 50 percent of the people killed by lightning in the state of Colorado
between 1980 and 1991 were climbing mountains.
- The fear of lightning is called
keraunophobia.
Keraunophobia should be a fear shared by all people when the damaging
capabilities of lightning are reviewed. It is one of nature’s most powerful and
deadly forces, one to be respected and admired.
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