Question: What Causes Lightning
Answered by Justin Caudell
Lightning is one of the most beautiful displays in nature. It is also one of the
most deadly natural phenomena known to man. Summer, which officially started
June 21, is the peak season for lightning, and this week, June 24 through June 30,
is Lightning Safety Awareness Week in the United States.
I have always found lightning fascinating, yet also frightening, but I still feel a
sense of awe watching the brilliant, jagged lines exploding from the sky with strobe
like flashes turning night into day. Lightning is both dramatic and irresistible. But
what causes it?
Lightning is produced in thunderstorms when liquid and ice particles above the
freezing level collide, and build up large electrical fields in the clouds. Once these
electric fields become large enough, a giant spark occurs between them, like static
electricity, reducing the charge separation. The lightning spark can occur between
clouds (the kind which is good to watch), between the cloud and air, or between
the cloud and ground (WATCH OUT!).
Cloud to ground lightning usually occurs near the boundary between the
updraft region where the darkest clouds are, and the downdraft/raining region with
the lighter, fuzzy appearance. Sometimes, however, the lightning bolt can come out
of the side of the storm, and strike a location miles away, seemingly coming out of
the clear blue sky.
As long as a thunderstorm continues to produce lightning, you know that the
storm still has active updrafts and is still producing precipitation. The temperature
inside a lightning bolt can reach 50,000 degrees Fahrenheit, hotter than the
surface of the sun. Objects that are struck by lightning can catch on fire, or show
little or no evidence of burning at all.
Lightning is one of the leading claims filed by insurances companies, causing
about 5 billion dollars of economic impact each year in the U.S. But human beings
are also in the cross hairs of lightning.
In the United States an average of 66 people are killed each year by lightning.
In 2006, there were 47 confirmed deaths and 246 confirmed injuries. The injury
number is likely far lower though than what it should be because many people do
not seek help or doctors do not record it as a lightning injury.
People struck by lightning suffer from a variety of long-term, debilitating
symptoms, including memory loss, attention deficits, sleep disorders, numbness,
dizziness, stiffness in joints, irritability, fatigue, weakness, muscle spasms,
depression, and an inability to sit for long.
To avoid the dangers of lightning, seek safe shelter when you first hear
thunder, see dark threatening clouds developing overhead or lightning. Count the
seconds between the time you see lightning and hear the thunder. You should
already be in a safe location if that time is less than 30 seconds. Stay inside until
30 minutes after you last hear thunder.