As we enter mid-spring and the weather finally begins to warm up a bit, we expect to see quite a few thunderstorms in Oregon. Inspiring awe in some while scaring the pants off others (but not ME, I'm definitely not scared of lightning. No sir,) it is no surprise that cultures all over the world associate lightning with deity. But what exactly is it?
During an electrical storm, the upper portion of the storm clouds has a positive charge and the lower portion has a negative charge. It is not quite clear how the clouds attain these charges in the first place, but one theory is that different forms of liquid (vapor, water and ice droplets) collide as they rise and fall within a cloud. In the collision, electrons are knocked off of the rising moisture and they gather at the bottom of the cloud, creating the negative charge. It is thought that rising moisture then carries a positive charge to the top of the cloud. The charge separation within the cloud is what creates an electric field, the strength of which is related to the amount of charge buildup in the cloud.
When the electric charge inside the cloud becomes very strong, the air becomes ionized (the positive ions and electrons are spaced further apart than before and the electrons can move more freely.) The strong ionization causes the air to begin to break down, allowing for currents to flow in an attempt to neutralize the charge. These currents are called leaders, and they provide a path through the cloud for the lightning to follow. The initial (or stepped) leader does not move smoothly, but jumps in a jagged fashion. Many leaders form at the same time, but the first one to make contact with the ground is the one that gets the lightning.
The entire process is a bit more complicated, but there you have the basics of how lightning is formed. Lightning is much too powerful for even the best of surge protectors to protect against, and it can reach temperatures of 54,000 °F. (For comparison- the surface of the sun is only about 9,900 °F.) An average bolt of lightning carries about 30,000 amps. A single ampere of current is all it takes to kill a human!
Lightning is a complex phenomenon with many variations and exceptions. Sometimes it shows up in the most unexpected of places.
For example, do you know:
Why We See Lightning During Volcanic Eruptions?
If you saw photos of the eruption of Icelandic volcano Eyjafjallajökull that erupted in 2010, you may have seen lightning within the plumes of smoke and thought that they surely must be photoshopped. Not so!
There is still research being conducted into the definitive cause behind lightning within the smoke plumes of volcanoes, but the general consensus involves, of all things, dust. The idea is that dust/smoke/ash particles carry small charges that become amplified during the chaos of rushing out of a volcano. With every collision of one particle with another, the charges become more and more polarized until lightning is inevitable because the polarization becomes too great for the air to resist the flow of electricity. The lightning neutralizes the charge separation, essentially relieving the tension of polarization.
There is another lesser known type of volcanic lightning, however, which occurs right at the mouth of the volcano and is much less orderly (not the ordinary branching, bolting lightning we're used to seeing), manifesting as chaotic sparks probably as the result of a heavy charge within the volcano itself.
How Many Different Kinds of Lightning There Are?
The answer to this question depends on who you ask, and what you consider a "kind" of lightning. The typical classifications are as follows:
Cloud-to-cloud (intercloud, which is lightning moving between separate clouds, and intracloud, which is lightning moving within the same cloud).
Cloud-to-ground (Less common but more dangerous than cloud to cloud. If anything on the earth is struck by lightning, it was cloud-to-ground.) Cloud-to-ground lightning is more complex than a simple bolt shooting straight from a cloud, however, and includes charges moving up and down from both the cloud and the ground.
Cloud-to-sky (Also known as sprites, cloud-to-sky lightning occurs in the upper atmosphere. They lack the hot temperatures of other types of lightning, and usually have a reddish-orange hue.)
Lightning is also sometimes further specified as:
Ribbon lightning (Successive strokes of lightning are displaced by wind, resulting in a broadened appearance, almost like a double-exposed photo).
Bead lightning (The decay of the luminosity of the bolt of lightning, resulting in a beaded appearance. This happens very quickly and is difficult to capture.)
St. Elmo's Fire This is not actually lightning, but often closely associated with it and seen during electrical storms. St. Elmo's Fire (not to be confused with ball lightning as it often is) is the result of a gap in electrical charge. It's made of plasma (ionized air that emits a glow) and, while lightning is the movement of electricity from a charged point, St. Elmo's Fire is a coronal discharge that sparks up in the place where there is a drastic difference in charge between the air and an object like the mast of a ship or the steeple of a church. St. Elmo's Fire is the same thing that happens in a fluorescent tube- essentially a continuous spark, glowing blue because of the particular combination of air molecules. It may also take on a purple hue.
St. Elmo's Fire is very difficult to find accurate images or videos of. Many videos exist that claim to be St. Elmo's Fire but are actually just static discharge (a frequent occurrence around airplanes in the midst of storms). An easy way to tell the difference is that St. Elmo's Fire does not look like lightning- instead it emits a steady glow.
Ball lightning- The most mysterious type of "lightning", there is some dispute among scientists as to whether ball lightning actually exists. Arc faults along power lines (which appear as large, impossibly bright balls of light) and photographic anomalies are both to blame for the confusion.
How to Stay Safe During a Thunderstorm?
Lightning regularly strikes water, so never go swimming or boating during a storm. If you are in the water when a storm begins, get out of the water as fast as you can.
Lightning strikes will follow anything that conducts electricity, so stay off your landline phone during a storm and turn off/unplug your computers. If lightning strikes your house, even the most powerful of surge protectors will have a hard time protecting your equipment. (Radio waves do not conduct electricity, so as long as your cell phone is not plugged in to an outlet and you are not standing outside during the storm with the metal device held to your face, it is safe to use it. They do not inexplicably "attract" lightning more than any other object with metal in it).
Lightning does in fact strike twice (the Empire State building is struck 20-25 times a year), so don't rely on old adages for your safety information.
If you are caught in a thunderstorm and cannot get inside to safety, crouch low to the ground but do not lay flat. Try to keep as much of your body from touching the ground as possible, because you are in more danger of being injured by currents traveling across the ground after a lightning strike than of being stricken directly by a bolt.
A flash-to-bang (seeing lightning to hearing thunder) ratio of 5 seconds equals one mile of distance from the lightning. Ten seconds equals 2 miles, etc.
Lightning in Mythology
One has only to view an electrical storm themselves to understand why so many people have associated lightning and thunder with deity. A few popular myths and legends about lightning:
Zeus (Jupiter to the Romans) is the planetary god of thunder, and his primary weapon is the thunderbolt (given to him by the Cyclops).
The Thunderbird common to North American indigenous cultures is said to create thunder by the beating of its wings, and lightning is made by glowing snakes that it carries or directly from its eyes.
Thor is the Norse hammer-wielding god of thunder.
There is so much more to learn about lightning in all of its various incarnations. It is a stark reminder of the incredible powerful forces of nature that surround us on all sides. Despite how much we learn about it on a scientific level, we may always be inclined to associate this incredible force with deity.
