-
- One of a series of stories covering the
quadrennial International
- Conference on Atmospheric Electricity,
June 7-11, 1999, in
- Guntersville, Ala. June 18, 1999: Either
lightning is
- attracted to testosterone, or men spend
an inordinate amount of time
- outdoors swinging metal objects about.
Men are struck by lightning
- four times more often than women.
-
- According to a study entitled "Demographics
of U.S. Lightning
- Casualties and Damages from 1959 - 1994,"
by Ronald L. Holle and Raúl
- E. López of the National Severe
Storms Laboratory and E. Brian Curran
- of the National Weather Service, males
account for 84% of lightning
- fatalities and 82% of injuries.
-
- Men can take comfort in the fact that
the actual number of deaths and
- injuries from lightning strikes has decreased
in the past 35 years.
- Holle's team attributes 30 percent of
the decrease in lightning deaths
- to improved forecasts and warnings, better
lightning awareness, more
- substantial buildings, and socioeconomic
changes. They attribute an
- additional 40 percent to improved medical
care and communications.
-
- The National Weather Service publication
Storm Data recorded 3,239
- deaths and 9,818 injuries from lightning
strikes between 1959 and 1994.
- Only flash floods and river floods cause
more weather-related deaths.
- But according to Dr. Elisabeth Gourbière
of the Electricitie de
- France, Service des Etudes Médicales,
only 20 percent of lightning
- victims are immediately struck dead.
Still, many doctors do not fully
- understand how to treat the injuries
of the other 80 percent of
- lightning victims who survive a strike.
-
- Says Gourbière, "The pathology
of lightning, or keraunopathy, is known
- only to a few specialists."
-
- Most doctors are more familiar with electrical
shocks, such as those
- received by industrial workers when they
have an accidental run-in
- with high-voltage equipment. But lightning
injuries are not the same
- as electrical shocks. For one thing,
the contact voltage of a typical
- industrial electrical shock is 20 to
63 kilovolts, while a lightning
- strike delivers about 300 kilovolts.
-
- Industrial shocks rarely last longer
than half a second (500
- milliseconds) because a circuit breaker
opens or the person is thrown
- far from the live conductor. Lightning
strikes have an even shorter
- duration, only lasting up to a few milliseconds.
Most of the current
- from a lightning strike passes over the
surface of the body in a
- process called "external flashover."
-
- Both industrial shocks and lightning
strikes result in deep burns at
- point of contact - for industry the points
of contact are usually on
- the upper limbs, hands and wrists, while
for lightning they are mostly
- on the head, neck and shoulders. Industrial
shock victims sometimes
- exhibit deep tissue destruction along
the entire current path, while
- lightning victims, burns seem to center
at the entry and exit points.
- Both industrial shock and lightning victims
may be injured from
- falling down or being thrown, and the
leading cause of immediate death
- for both is cardiac or cardiopulmonary
arrest.
-
- If you survive a shock, you still have
to deal with the consequences
- of the electrical burns. Industrial shock
burns can lead to kidney
- failure, infection, muscle and tissue
damage, or amputation. Lightning
- burns are exceptionally life threatening
(see box at the end of this
- story).
-
- Right: High voltage electrical equipment
can cause severe shocks
- and burns slightly similar to those from
lightning strikes.
-
- Gourbière says that 70 percent
of lightning survivors experience
- residual effects, most commonly affecting
the brain (neuropsychiatric,
- vision and hearing). These effects can
develop slowly, only becoming
- apparent much later.
-
- Feel the Burn
-
- If you'd like to experience a lightning
strike, go golfing one Sunday
- in July around 4 p.m. If you're really
determined, be sure you do it
- in Florida.
-
- Florida has twice as many lightning casualties
(deaths and injuries
- combined) as any other state. Most lightning
casualties occur in the
- afternoon - two-thirds between noon and
4 p.m. local standard time
- with a casualties maximum at 4. Sunday
has 24% more deaths than other
- days, followed by Wednesday. Lightning
reports reach their peak in
- July.
-
- Many lightning victims had been walking
in an open field or swimming
- before they were struck. Other lightning
victims had been holding
- metal objects such as golf clubs, fishing
rods, hay forks, or
- umbrellas. But even those not holding
metal objects are as likely to
- be struck by lightning as a bronze statue
of the same size.
-
- When you hear thunder, you are already
within the range where the next
- ground flash may occur. N. Kitagawa of
Central Lightning Protection,
- Inc. and A. Sugita and S. Takahashi of
Franklin Japan determined the
- average intervals between lightning strikes
in order to estimate how
- much time someone has to seek shelter.
Their news is far from
- encouraging.
-
- "It is concluded that there exists
no safe time interval during which
- a human is free from direct strikes,"
they wrote.
-
- In an area with a radius of 500 meters
(1,640 ft), most of the
- intervals between lightning strikes range
from 0 to 600 seconds, with
- a maximum frequency of 40 seconds.
-
- The top ten states in number of lightning
casualties (deaths and
- injuries combined). Florida leads the
list, with twice as many
- casualties as any other state. Other
states represented are Georgia,
- Tennessee, North Carolina, New York,
Pennsylvania, Ohio, Michigan,
- Colorado and Texas.
-
- To avoid being struck by lightning, you
should seek shelter when you
- hear even the faintest thunder. Some
of the best places to take refuge
- are enclosed buildings, or cars and buses
(but don't touch the
- metal!). In case there are no safe spaces
nearby, bend into a
- crouching position until there is a break
in the storm.
-
- NASA's Global Hydrology and Climatology
Center - Lightning and
- atmospheric electricity research. Isolated
trees,
- telephone booths, and open structures
like gazebos or porches make poor
- lightning shelters. If there is a tall
object nearby, move as far away
- as possible - at least 2 meters (7 ft).
Standing next to tall isolated
- objects like poles or towers makes you
vulnerable to secondary
- discharges coming off those objects.
-
- According to L.G. Byerley III from Lightning
Protection Technology and
- W.A. Brooks, R.C. Noggle, and K.L Cummins
from Global Atmospherics,
- Inc., the growth of towers in the United
States has increased the
- amount of lightning strikes in certain
areas. Such towers include
- cellular telephone and wireless communications,
radio, microwave
- repeater, VHF communications and water
towers.
-
- The mechanism for how towers attract
lightning is not really
- understood. But scientists have known
for a long time that towers
- attract more lightning than the undisturbed
ground nearby.
-
- The tale of a family in North Carolina
clearly illustrates how towers
- can concentrate lightning strikes. In
1998, a 42 meter (138 ft) tall
- water tower was erected near Murfreesboro,
NC. This tower was about 45
- meters away from a farmhouse that was
situated on a one acre plot in a
- large open area of farmland. The family
had lived in the farmhouse for
- the past 10 years, and they had never
experienced any lightning
- damage. After the tower was erected,
5 separate discharges near the
- house occurred over a period of 5 months,
causing the deaths of 2
- trees, a fire in electrical equipment,
complete destruction of all
- phone wiring, and damage to electrical
fixtures.
-
- Lightning damages have been on the increase
in the past 35 years.
- Holle's team attributes most of this
increase to population growth.
- Storm Data recorded 19,814 property-damage
reports due to lightning in
- the United States from 1959-1994. Pennsylvania
has the largest number
- of damage reports, while the highest
rates of damage reports weighted
- by population are on the plains from
North Dakota and Oklahoma.
-
- According to Richard Kithil of the National
Lightning Safety
- Institute, most reports of the economic
impact of lightning are
- contradictory and underreported. The
National Weather Service Storm
- Data figures place the most recent yearly
losses at $35 million, but
- the process by which this figure is tabulated
is open to error. Storm
- Data collects much of its severe weather
information from newspaper
- reports. If an incident is not reported
in the paper or is overlooked
- by the Storm Data reviewer, it may not
get into the publication's
- statistical base.
-
- Kithil conducted his own study based
on insurance reports and other
- sources that keep track of weather damages,
and he came up with a much
- larger figure for the annual cost of
lightning strikes.
-
- "It seems reasonable to estimate
that there may be $4 to 5 billion in
- lightning costs and losses each year
in the US," said Kithil.
-
- There are currently several different
methods used to keep track of
- lightning strikes, but none of them can
be considered perfect. Medical
- reports, for instance, sometimes report
"burns" as the primary cause
- of death, with lightning listed as a
secondary effect. Despite such
- instances of underreporting, the methods
used in the United States to
- track lightning strikes are considered
to be the best available.
-
- "We work with people from other
countries who wish they had what we
- have," said Holle.
-
- Humans versus Lightning
-
- To stand against the deep dread-bolted
thunder?
- In the most terrible and nimble stroke
- Of quick, cross lightning?
- (Wm. Shakespeare, "King Lear",
Act 4, Scene 7)
-
- In the contest between people and lightning,
lightning wins. Although
- lightning rarely strikes more than one
person at a time, over the
- course of a year the damages, deaths
and injuries add up to make
- lightning a serious threat. By studying
the outcome of human-lightning
- encounters, scientists hope to find more
ways to prevent such meetings
- from occurring in the first place.
-
-
- Most Typical Disorders Associated
with
- Lightning Strikes
-
- (from "Lightning Injuries to Humans
in France" by Dr. Elisabeth
- Gourbière of the Electricitie
de France, Service des Etudes Médicales)
-
-
- Lightning deaths (~20%)
- -Asystole/Ventricular fibrillation
- -Inhibition of brainstem respiratory
centers
- -Multi-system failure (delayed death)
-
- Cardio-pulmonary injuries
- -Arrhythmias - Arterial pressure changes
- -Electrocardiographic changes
- -Myocardial damages (infarction)
- -Cardiac dysfunction
- -Pulmonary edema - Respiratory distress
syndrome
-
- Neurologic/psychiatric injuries
- -Loss of consciousness/coma
- -Amnesia/Anxiety/Confusion/Aphasia/Seizures
- -Electroencephalographic abnormalities
- -Brain/Cerebellum damages
- -Numbness/Weakness in limbs/Partial
or complete (but temporary)
- paralysis
- -Neuropathy/Pain syndromes
- -Spinal cord injury/Parkinsonism
- -Sleep and memory disorders/Concentration
- disturbances/Irritability/Depression/Various
other disturbances
- such as headaches, tiring easily, lightning
storm phobia, etc.
- -Post traumatic Stress Disorder
-
- Burns and Cutaneous marking
- -Small, deep entry/exit points (typical)
- -Contact, metal chain heating (typical)
- -Superficial linear
- -Flash
- -Lichtenberg figures (arborescent, fern-like
- markings):pathognomonic(on trunk, arms,
shoulders)
-
- Clothing, shoes
- -Exploded off, torn off, shredded, singed
-
- Blunt traumas (explosion)
- -Contusion, internal hemorrhage (brain,
lungs, liver, intestine)
- -(rarely) Fractures (skull, cervical
spinal column, extremities)
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