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 Is A Random, Chaotic And Dangerous Fact Of
At any given moment, there are 1,800 thunderstorms in
progress somewhere on the earth. This amounts to 16 million
storms each year! Scientists that study lightning have a
better understanding today of the process that produces lightning,
but there is still more to learn about the role of solar
flares on the upper atmosphere, the earth's electromagnetic
field, and ice in storms. We know the cloud conditions needed
to produce lightning, but cannot forecast the location or
time of the next stroke of lightning. There are lightning
detection systems in the United States and they monitor an
average of 25 million
from the cloud to ground every year!
Lightning has been seen in volcanic eruptions, extremely
intense forest fires, surface nuclear detonations, heavy
snowstorms, and in large hurricanes, however, it is most
often seen in thunderstorms. A thunderstorm forms in air
that has three components: moisture, instability and something
such as a cold front to cause the air to rise. Continued
rising motions within the storm may build the cloud to
a height of 35,000 to 60,000 feet (6 to 10 miles) above
sea level. Temperatures higher in the atmosphere are colder;
ice forms in the higher parts of the cloud.
Ice In The Cloud Is Critical To The Lightning Process
Ice in a cloud seems to be a key element in the development
of lightning. Storms that fail to produce quantities of
ice may also fail to produce lightning. In a storm, the
ice particles vary in size from small ice crystals to
larger hailstones, but in the rising and sinking motions
within the storm there are a lot of collisions between
the particles. This causes a separation of electrical
charges. Positively charged ice crystals rise to the top
of the thunderstorm, and negatively charged ice particles
and hailstones drop to the middle and lower parts of the
storm. Enormous charge differences (electrical differential)
How Lightning Develops Between The Cloud And The Ground
A moving thunderstorm gathers another pool of positively
charged particles along the ground that travel with the
storm. As the differences in charges continue to increase,
positively charged particles rise up taller objects such
as trees, houses, and telephone poles. Have you ever been
under a storm and had your hair stand up? Yes, the particles
also can move up you! This is one of nature's warning
signs that says you are in the wrong place, and you may
be a lightning target!
The negatively charged area in the storm will send out
a charge toward the ground called a stepped leader. It
is invisible to the human eye, and moves in steps in less
than a second toward the ground. When it gets close to
the ground, it is attracted by all these positively charged
objects, and a channel develops. You see the electrical
transfer in this channel as lightning. There may be several
return strokes of electricity within the established channel
that you will see as flickering lightning.
The lightning channel heats rapidly to 50,000 degrees.
The rapid expansion of heated air causes the thunder.
Since light travels faster than sound in the atmosphere,
the sound will be heard after the lightning. If you see
lightning and hear thunder at the same time, that lightning
is in your neighborhood!
Negative Lightning And Positive Lightning
Not all lightning forms in the negatively charged area
low in the thunderstorm cloud. Some lightning originates
in the cirrus anvil at the top of the thunderstorm. This
area carries a large positive charge. Lightning from this
area is called positive lightning. This type is particularly
dangerous for several reasons. It frequently strikes away
from the rain core, either ahead or behind the thunderstorm.
It can strike as far as 5 or 10 miles from the storm,
in areas that most people do not consider to be a lightning
risk area. The other problem with positive lightning is
it typically has a longer duration, so fires are more
easily ignited. Positive lightning usually carries a high
peak electrical current, which increases the lightning
risk to an individual.
For more on the science of lightning: