Storm Prep Saturday: Lightning

Growing up in the “lightning capital of the United States” aka Florida, we learned a lot about the power and dangers of lightning all throughout school. The most important things to know: don’t be outside during a lightning storm, and stay away from anything that conducts electricity! If you can hear thunder, lightning is close enough to strike you. Take precautions when you are out and about if there is a storm rolling in. Make sure you have a safe place you can get to when the storm starts. Lightning strikes the United States about 85 million times per year, and kills an average of 49 people per year. Don’t become a statistic, give lightning the respect it deserves.

lightning strike

Dangers

There are so many dangers that can be attributed to lightning. The biggest dangers is loss of life, usually from those who don’t heed warnings and move to a safe location when there is lightning in the vicinity. Lightning strikes also cause an average of more than $1 billion in insured losses each year. Most wildfires are started from a lightning strike to a dry area, causing the fire which can then threaten life and property as an indirect result of the lightning.

Lightning usually will strike the tallest object around, but not always. Lightning can strike in an open field even if there are trees nearby. Typically, it goes for the tallest thing because it’s closer to the clouds so less air to go through. Also, it is a myth that lightning never strikes the same place twice. It can strike the same object multiple times in one lightning storm.

lightning fatalities

Formation

Lightning is a giant spark of electricity in the atmosphere between clouds, the air, or the ground. In the early stages of development, air acts as an insulator between the positive and negative charges in the cloud and between the cloud and the ground. When the opposite charges builds up enough, this insulating capacity of the air breaks down and there is a rapid discharge of electricity that we know as lightning. The flash of lightning temporarily equalizes the charged regions in the atmosphere until the opposite charges build up again.1

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Lightning can be categorized as cloud-to-ground or cloud-to-sky lightning. Cloud-to-ground lightning is, as the name suggests, lightning that strikes between the clouds and the ground. This is the lightning that we most need to worry about. Cloud-to-ground lightning is what forms when negatively charged particles reach down towards the ground, and meet with positively charged particles, created a channel for a powerful electrical charge to stream through, which we see as lightning. If it happens multiple times in the same channel the lightning seems to flicker on and off for a few seconds.

There are many types of cloud-to-sky lightning strikes, but most of those are not dangerous to people on the ground. The only time these pose a significant danger is if you are in a plane flying through a storm. One common type of cloud-to-sky lightning is intra-cloud lightning, which lights up within a cloud but doesn’t hit anything on the ground. You may also see the lightning travel between clouds, which is cloud-to-cloud lightning. Spider lightning (my favorite to watch) is the lightning that spreads out on the underside of a cloud. “Heat Lightning” usually refers to lightning that you can see in the clouds, but it’s too far off to hear the thunder.

types of lightning
Src: http://ffden-2.phys.uaf.edu/212_fall2003.web.dir/Shawna_Sastamoinen/types.htm

Be Weather Alert

Currently, there are no watches/warnings specific to lightning, but it is a common occurrence with most storms, so if you are under a watch or warning for a thunderstorm, tornado, hurricane, etc. then know there is a high probability of lightning. Weather forecasters can predict if a storm is likely to cause lightning, but because of the unpredictability of lightning, they can’t say where and when it will strike. If you are planning any outdoor activities, keep an eye on the weather and make sure you give yourselves ample time to get inside if a storm approaches.

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Thunder is caused by lightning. The bright light of the lightning flash caused by the return stroke mentioned above represents a great deal of energy. This energy heats the air in the channel to above 50,000 degrees F in only a few millionths of a second! The air that is now heated to such a high temperature had no time to expand, so it is now at a very high pressure. The high pressure air then expands outward into the surrounding air compressing it and causing a disturbance that propagates in all directions away from the stroke. The disturbance is a shock wave for the first 10 yards, after which it becomes an ordinary sound wave, or thunder. Thunder can seem like it goes on and on because each point along the channel produces a shock wave and sound wave.1

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During a Lightning Storm and After

Indoors Safety:

  • Stay off corded electronics
  • Avoid water such as sinks, tubs, showers, etc.
  • Stay away from windows
  • Do not lie on concrete floors or lean on concrete walls
  • Stay inside until 30 minutes after you last hear thunder
  • Unplug sensitive electronics and turn off the a/c

Outdoors Safety:

  • Always try to get inside a sturdy building
  • If a building isn’t available, a vehicle is next safest with windows up but DO NOT touch any of the metal
  • If outside, get to the lowest area that isn’t flooded
  • Don’t lie flat on the ground, crouch with head between your knees and smallest part of feet touching ground
  • Don’t stand under a tree or near anything that conducts electricity such as a metal fence
  • Don’t use a cliff or overhang for shelter as it can cave in
  • Get out of and away from any water

lightning over city

Personal Experience

As I said, I grew up in Florida which used to be called the “lightning capital of the world” but is now just the “lightning capital of the United States.” Florida gets an average of at least 90-100 days per year with lightning storms. I’ve learned to respect lightning and had it ingrained in me that lightning is not something to be messed with. When I was in high school I was on the golf team, and my coach had a lightning detector that he kept on him at all times. It detected lightning within 10 miles, and he would come get us all on the golf cart and into the clubhouse. We had many practices and matches get delayed because of lightning.

Even before that, I remember one time staying the weekend with my cousins when their apartment was struck by lightning. We were just going to bed, one of my cousins and my aunt just got home form his practice (I don’t remember what sport he was playing) and just got out of the shower. We were laying down and heard an incredible crash outside that scared us all and we went running to my aunt and uncle’s bedroom. Lightning had struck and actually fried my uncle’s computer. Thankfully he was printing something at the time and not touching his corded mouse.

Related:  Wildfires

In college, one of the apartment we lived at had a different building catch fire because of a lightning strike. We were watching the storm from inside, and we saw a flash of lightning that seemed so close. My husband insisted it wasn’t as close as we thought. Next thing we knew there were reports of a building on the other side of the complex that caught fire after it was struck by lightning.

I could go on and on with lightning stories. Out on the boat and had to get to the island because it was safer than the boat with the huge metal wakeboard tower. Being at waterparks and theme parks that get shut down for a while because of lightning. In Florida, lightning is a part of everyday life.


Sources:

  1. http://www.nssl.noaa.gov/education/svrwx101/lightning/
  2. http://www.lightningsafety.noaa.gov/resources/ttl6-10.pdf

lightning

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