Lightning is one of the most amazing weather phenomena and provides the most fabulous free show on earth.. Every year in US alone more than sixty people are killed by lightning strikes and hundreds more get struck by lightning but somehow manage to survive.
A single lightning bolt carries an average of 40 kilo amperes of electricity. This is the equivalent to 40,000amps. A radio runs on around 3amps and an electric iron about 5 amps. So one lightning bolt could power 8,000 electric irons. Some bolts can carry three times this amount of electricity and this depends on how long they are. Longer bolts are more powerful.
When a thunder cloud moves over the surface of the earth, an equal but opposite charge is generated in the earth. Once the charge becomes strong enough an electrical discharge occurs in the cloud, or between the clouds, and a lightning bolt is formed. There are many different kinds of lightning which behave in slightly different ways.
Anvil
Anvil lightning comes from the top of those anvil shaped clouds which are typical of thunderstorms. The lightning bolt comes out of the cloud almost horizontally until it turns and heads for earth.
Ball
Ball lightning is floating balls of lightning which vary in size from very small upwards. It can move fast, or slow and sometimes hovers in one place. It has also been know to hiss,
or spin and sometimes to dissipate with a loud bang.
Bead
Bead lightning doesn't flash at all once. Small 'beads' flash at a time creating a kind of string of beads effect. This may be related in some way to ball lightning.
Fork
Photo credit: NOAA
Forked lightning is shaped a bit like a branch from a tree. This happens when two or more return charges follow the same, or only slightly different paths.
Ribbon
Strong winds can change the shape of a lightning bolt and ribbon lightning is formed when the wind blows the lightning outwards and causes it to spread out.
Sheet
Photo Credit: Conservativehippie.com
Sheet lightning occurs where the lightning lights up the clouds at a distance and it looks like a sheet moving across the sky.
Staccato
With Staccato lightning the charge runs from ground to air. It is a leader stroke of lightning with the same return path.
Photo Credit: Captain Fred Woo, H.K.
There are other shapes and even different colours of lightning. It can run along many different routes and may be cloud to air, cloud to cloud, or even cloud to ground. There is also a very special kind of lightning that has been the subject of many a sailor's tale. Old books about seafarers and travellers mention St. Elmo's Fire. It is named after St. Erasmus of Formiae, the patron saint of sailors and has long been regarded by seafarers with superstition. It occurs when ionization of air molecules around an object causes a faint glow which is easily seen in poor light conditions. Sailors are said to have seen whole ships sailing along surrounded by St. Elmo's Fire.
PHOTO CREDIT: All graphics : Wikipedia Creative Commons License (unless otherwise stated.)
Nice photos.