Different Types of Lightning (credit: The National Severe Storm Laboratory & The National Weather Service)

​DISCUSSION: Lightning is one of the most dangerous types of weather phenomena. As of September 3rd, 2018, according to the National Weather Service, in 2018 alone there have been 20 deaths from lightning strikes in the United States so far. It is recommended to stay inside when there is an upcoming thunderstorm.
 
The National Severe Storms Laboratory (NSSL) has a page that lists and describes the different types of lightning. Lightning is formed by energy transferred from positive and negative charges in clouds or the ground. There are three primary types of lightning which include: cloud-to-ground (the most commonly known type), cloud-to-air, and cloud-to-cloud.
 
With cloud-to-ground lightning, the rapid discharge of lightning is a channel of negative charge that is attracted to the positively charged ground. Once the two charges are connected by the stepped leader (the initial invisible connection between the two charges) and a positive return stroke from the positively charged ground, the electrical current that is seen as lightning forms. Sometimes, the cloud can be positively charged, and the ground negatively charged, but this doesn't occur as often. The NSSL states that cloud-to-air and cloud-to-cloud lightning have 5 to 10 times more lightning strikes than cloud-to-ground. (Below is a picture of cloud-to-ground lightning.)

​Cloud-to-air lightning is described by the National Weather Service (NWS) as “lightning that occurs when the air around a positively charged cloud top reaches out to the negatively charged air around it.” In other words, these lightning strikes are an attraction between clouds and air that are opposite charges and never reach the ground. Most of the time though, the positive charge forms atop of a storm cloud and is attracted towards a negative charge in the air nearby. (Below is a picture of cloud-to-air lightning.)

​Lastly, there is cloud-to-cloud lightning. The NWS describes this type of lightning as “lightning that occurs between two or more separate clouds.” This lightning forms by one cloud being a mostly negative charge and another being a mostly positive charge, causing the attraction between the two. The NSSL explains that a type of cloud-to-cloud lightning called a “spider lightning” are formed underneath stratiform clouds (low-level, thin clouds that may produce a light drizzle) and flashes travel horizontally. (Below is a picture of cloud-to-cloud lightning.)

There are a few more lightning types that aren’t necessarily categorized as part of the three main types of lightning. These lightning types include: red sprites, blue jets, and elves. Red sprites usually occur above a large thunderstorm and are normally a red color. Red sprites usually occur during a cloud-to-ground lightning strike. They can be seen from space as they extend up to 60 miles above a cloud top. They can reach all the way to the mesosphere! Blue jets also form above a storm cloud but, unlike red sprites, they are not associated with cloud-to-ground lightning. They reach up to 22-35 miles above a cloud and can be seen by aircraft. They can sometimes just reach the stratosphere. Lastly, elves are described as a glowing disk that can extend up to 300 miles. This upper-atmospheric lightning can reach the ionosphere. The Space Shuttle discovered elves in 1992. (Below is a diagram provided by the NSSL of red sprites, blue jets, and elves.) 

Lightning is important to understand and a weather phenomenon that happens constantly on this planet. Knowing what types of lightning occur at what height in the atmosphere is important to assure aircraft and spacecrafts have safe travel paths. Lower-atmospheric lightning is a life-threatening danger to humans and being more cautious when lightning is forecasted could save lives. 

To learn more about other important educational topics in meteorology from around the world, be sure to click here!

© 2018 Weather Forecaster Brittany Connelly