Each spark of lightning can
reach over five miles in length, soar to temperatures of approximately 50,000
degrees Fahrenheit, and contain 100 million electrical volts.
Lightning
and Lightning safety introduction:
The
greatest number of lightning deaths and injuries in the
While nearly all people take some protective
action during the most dangerous part of storms, many leave themselves
vulnerable as thunderstorms approach, depart or are near by. Lightning can
strike up to 10 miles from the main area of the thunderstorm. That’s about the
distance you can hear thunder from the storm. In some instances when storms are
10 miles away, it can be hard to tell if a storm is nearby. However, if you can
hear thunder, you are at risk from being struck by lightning
Inside homes, people must avoid activities
which put them at risk from a possible lightning strike. In particular, people
should stay away from doors and windows and avoid contact with anything that
conducts electricity. People may also want to take action well before the storm
threatens in order to protect property within their homes, such as unplugging
electronic equipment.
Lightning can occur completely within the
thunderstorm cloud or between the cloud and the ground. In-cloud lightning
generally occurs between positive charges at the top of the clouds and negative
charges at the bottom of the cloud. Cloud to ground lightning occurs between a
cloud and the ground. Lightning can also occur between clouds. Cloud to ground
lightning can be categorized as negative flashes and positive flashes. Negative
flashes usually occur between negative charges in the lower part of the storm
and the positive charges in the ground under and near the cloud base. Prior to a
flash, an almost invisible negatively charged channel of air forms near the
cloud base and surges downward near the ground. As the step leader approaches
the ground, streamers of positive charges shoot up from trees, buildings and
other high objects on the ground. When one of these streamers meets the step
leader, the connection is complete and a surge of electrical current moves from
the ground to the cloud causing the visible return stroke that we call
lightning.
Why
do some clouds produce lightning and others don’t?
Positive
flashes usually occur between the positively charged upper level of the storm
and the negatively charged areas surrounding the storm. The process of the
positive flash is similar to that of the negative flash except that in this
case, the positive channel originates from the anvil of the storm and surges
downward. Streamers of negative charges shoot up to meet the positively charged
channel as it approaches the ground. When a connection is made, a positive flash
of lightning occurs. Because the distance between the ground and the anvil is
much greater than the distance between the ground and the cloud base, a much
larger electric potential is needed to initiate a positive flash of lightning.
For this reason, positive flashes are infrequent and widely scattered around the
storm, but they generally involve the exchange of a much greater charge and are
usually much more destructive
The greatest danger
associated with positive charges, however, is that they strike in areas where
most people think they are safe from storm. They can strike well beyond the area
where rain is falling and well beyond the area where lightning and thunder are
occurring. Consequently, many victims are caught completely off guard. Don’t
become a lightning victim: get to a safe place sooner and to stay there longer.
Remember, if you can hear thunder, you are within striking distance of
lightning.
Lightning
Safety Outdoors:
While no one can completely
eliminate the risk of being struck by lightning, by using some basic safety
rules, you can greatly reduce your risk of becoming a lightning victim. First,
plan ahead. If thunderstorms are predicted, postpone or cancel outdoor
activities so you can avoid a potentially dangerous situation. Second, monitor
weather conditions. Watch the sky for any signs of developing or approaching
storms and leave time to get to a safe place. Third, if the sky looks
threatening or you hear thunder, immediately seek shelter inside a substantial
building. Remain there for at least 30 minutes after the last flash of lightning
is seen or the last thunder is heard. Some lightning victims have actually made
the mistake of returning outside before the threat is over. And fourth, if you
are caught outside in a thunderstorm, you should try and minimize your risk of
being struck. Stay away from tall objects such as trees and poles.
Stay away from things that
conduct electricity such as metal bleachers or metal fences. Also, try to make
yourself a small a target as possible and minimize your contact with the ground.
If you or your children are involved in organized outdoor activities, make sure
the officials in charge have and follow a specific lighting safety plan. Don’t
be afraid to ask. Coaches, umpires, or school and camp counselors need to know
to stop activities early so there’s a enough amount time to get participants
and spectators to get to a safe place before the lightning threat becomes
significant. If you can’t get to a substantial building, a hard-topped metal
vehicle is a good shelter. Be sure to roll up windows and make sure the
occupants avoid contact with any metal inside the vehicle. Finally, don't forget
the safety of your outside pets. Dog houses are not safe, and dogs that are on a
metal chain or wire runner are particularly vulnerable to a nearby lightning
strike.
Safe
shelters and indoor safety:
There are three main ways
lightning enters homes and buildings: direct strike; through wires or pipes that
extend outside the structure or through the ground. Regardless of the method of
entry, once inside, lightning can travel through electrical and phone lines,
plumbing, and radio and TV reception systems. Lighting can also travel through
any metal wires or bars in concrete walls or flooring.
Phone use is the leading cause of indoor
lighting injuries in the U.S. Lightning can travel long distances in both phone
and electrical wires, particularly in rural areas. Stay away from windows and
doors as these can provide a path for a direct strike to enter a home. Do not
lie on the concrete floor of a garage as it likely to contain a wire mesh. In
general, a basement is a safe place to go during a thunderstorm. However there
are a few things to keep in mind. Avoid contact with concrete walls as they may
contain metal reinforcing bars. Avoid washers and dryers since they not only
have contacts with the plumbing and electrical systems but also contain an
electrical path through the outside through the dryer vent. Lightning also
causes significant damage to personal property each year. In addition to direct
strike, lightning generates electrical surges that can damage electronic
equipment some distance from the electrical strike. To the extent possible,
unplug any appliances or electrical equipment from all conductors well before
the thunderstorm threatens. Don’t forget to disconnect televisions and radios
from outdoor antennas. If you plan to be away from your home when thunderstorms
are possible, be sure to unplug unneeded equipment before you leave.
Here’s a summary of
lightning safety tips for inside the home: Stay off porches. Stay away from
windows and doors. Avoid contact with corded phones and with electrical
equipment or cords. If you plan to unplug any electrical equipment, do so well
before the storm arrives. Avoid contact with plumbing. This includes washing
your hands, taking a shower or bath, washing dishes or doing laundry.
The
medical aspects of lightning:
If someone is struck by
lightning, it’s important that they receive the appropriate medical attention
immediately. Some deaths can be prevented if the victim is attended to promptly.
Lightning victims do not carry an electrical charge and are safe to handle.
First, have someone call 911 or your local ambulance service. Check to see that
the victim is breathing and has a pulse and continue to monitor the victim until
help arrives. Cardiac arrest is the immediate cause of death in lightning
fatalities. If necessary, begin cardio pulmonary resuscitation (CPR). If
possible, move the victim to a safer place. Don’t let the rescuers become
lightning victims. Lightning can strike the same place twice. Physically, only a
few lightning strike victims suffer burns. Due to the conductivity of the human
body, lightning burns are usually minor and most burns occur when objects next
to the body – such as rings, necklaces or metal coins – are heated by the
lightning. In addition, sweat vaporized by lightning can cause burns.
Mentally, lightning strike victims may face
many challenges that they have to live with for the rest of their lives. When
the brain is affected by a lightning strike, the person has difficulty with the
mental processes most of us take for granted. The person many suffer from
short-term memory loss and may have difficulty mentally storing new information
and accessing old information. Victims may often find it very difficult to carry
out more than one task at a time and may be easily distracted. Their personality
may change and they may become easily irritated. Victims often complain of being
easily fatigued and can become exhausted after a few hours of work. This may be
because mental tasks that were once automatic now require intense concentration
to accomplish. Although some victims may sleep excessively at first, after a few
weeks many find it difficult to sleep more than 2-3 hours at a time.
Another common long-term problem for survivors
is pain. Medically, pain is hard to quantify. Lightning strike victims often
have irreparable nerve damage from which they will suffer the rest of their
lives. The pain can be so bad that it affects the person’s ability to
function. Many survivors complain of chronic headaches, some of which are
intense and debilitating. It’s important to remember that while many lightning
victims survive, their lives are changed forever and their dreams for the future
– and those of their families – will never be the same.