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Lightning bolts come in all shapes and sizes

Weather Talk

POSTED: Tuesday, August 5, 2014 - 11:37am

UPDATED: Monday, December 8, 2014 - 11:32am

There is the traditional bolt, heat lightning, sheet lightning and even lightning in the shape of a ball!

My sister Lynn and I used to run around the house when we were kids and rub our feet on the carpet and produce static electricity and shock each other. (The dog was not amused Maybe you have grabbed the refrigerator handle or touched an object a received an static electric shock. The same thing occurs when lightning is made, but on a much bigger scale! In today’s “Weather Talk” I will talk about how lightning is formed, the types of lightning strikes and briefly describe the variety of forms lightning.

How is lightning formed?

Lightning is an electric current. To make this electric current, first you need a cloud.When the ground becomes hot, it heats the air above it and this warm air rises up. As the air rises, water vapor cools and forms a cloud. When air continues to rise, the cloud gets bigger and bigger. In the tops of the clouds, temperature is below freezing and the water vapor turns into ice. Now, the cloud becomes a cumulonimbus or thunderstorm cloud. Lots of small bits of ice bump into each other as they move around. All these collisions cause a build up of an electrical charge. After some time, the whole cloud fills up with electrical charges. Lighter, positively charged particles form at the top of the cloud. Heavier, negatively charged particles sink to the bottom of the cloud.When the positive and negative charges grow large enough, a giant spark occurs between the two charges within the cloud. This spark is lightning. This is like a static electricity sparks when something shocks you but on a much larger scale!

Types of Strikes

Cloud to ground -This is the discharge from the negative lower part of the cloud to the positively charged earth. The United States averages 25 million lightning strikes a year! The temperature of lightning to 50,000º F (27,700 degrees Celsius) or four times the temperature on the surface of the sun! A single bolt may contain as much a hundred million electrical volts! All thunderstorms do produce some sort of lightning. Cloud to ground is the most common form thought of when lightning is mentioned to people however it only constitutes 25% of all lightning however it is also the type that causes the most damage and is the most deadly.
Ground to cloud -The same as cloud to ground with the exception that usually a tall, earth-bound object, like a building or a tree, initiates the strike to the cloud

Cloud to cloud - Intra-cloud lightning is what we normally see, and is the most common form of lightning. Cloud to cloud appears as a flash within the cloud occurring between the positive and negative charges that are within the same thunder cloud. Cloud to cloud lightning produces the least amount of danger or damage.

“Bolt from the Blue”-  "Bolt from the Blue" is a cloud to ground lightning flash which typically comes out of the back side of the thunderstorm cloud, travels a large distance, more than 25 miles away, in clear air away from the storm cloud, and then angles down and strikes the ground. These lightning flashes are a very dangerous type of cloud to ground lightning flash, as they "appear" to come out of the clear sky.

Types of Lightning

Normal lightning – Cloud to ground, ground to cloud and cloud to cloud lightning definitions above.

Sheet lightning – This Normal lightning that is reflected in the clouds and appears as a sheet of light. The reflection of the clouds helps it sometimes light up a large entire section of the sky!

Heat lightning - Normal lightning near the horizon that is reflected by high clouds. Heat lightning usually occurs on “hot” days hence the name.

Ball lightning - This appears in the form of a glowing sphere, from the size of a golf ball to bigger than a beach ball, which drifts horizontally in the air usually only lasting a few seconds. It is still not fully understood why this occurs, one interesting theory that was recently found was by New Zealand researchers Abrahamson and Dinniss in 2000 is to do with the soil type at the place of the strike. A heated mixture with more carbon content than silicon can cause the silicon to separate out into a very light fluffy form which is capable of floating in air. The bolt temperature has to be of approximately 5 432 ºF (3000ºC). If lightning strikes soil with the right carbon and silicon mixture, a ball of silicon then would be created and due to its light nature would hover in the air. The light emitted then is believed to be the oxidization of the silicon as it is burning which would explain why the ball gives off such light and the fades away after all the silicon is burned.

Upper-atmospheric lightning or Ionosphere Lightning

Red sprite -A red burst that happens in the upper atmosphere above storm clouds, at an altitude range 30 to 56 mile (50–90 km) above the Earth's surface. and reaching a few miles in length up towards the stratosphere! The last usually less than a second, sometimes up to 2 seconds. Here is a link to video of red sprites on caught by Graduate student Jason Ahrns last summer during several flights over the in the National Center for Atmospheric Research's Gulf stream V research plane a part of a sprite-hunting team.

Blue jet - A blue, cone-shaped burst that occurs above the center of a storm cloud and moves upward towards the stratosphere at a high rate of speed. red sprites tend to be associated with significant lightning strikes, blue jets do not appear to be directly triggered by lightning they appear to relate to strong hail activity in thunderstorms. They are also brighter than sprites and, as implied by their name, are blue in color. The color is believed to be due to a set of blue and near-ultraviolet emission lines from neutral and ionized molecular nitrogen.

Now you know about how lightning forms, what are the three types of strikes and a little about all the types of lightning there are. Writing this article gives me an idea, the next time I see my sister I will kick off my shoes, run around on the carpet and give her a static shock for “old times sake”.

Read about more lightning facts in my recent “Weather Talk” “Monsoon Safety Awareness week- Lightning”

Chuck DeBroder, Chief Meteorologist
KTSM, NewsChannel 9, NBC, El Paso, TX

(Photo Credit: Mickey Gonzales- Photography Enthusiasts of El Paso (PEEP)

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