English Transcript
Próximamente transcripción en español
Production team: Elizabeth Smith, Pat Hyland, and Ross Forsyth Logo design and English transcription: Kathryn Geauer
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Pat Hyland: From the National Weather Museum and Science Center in Norman, Oklahoma, this is “When Did the Storm Begin,” a podcast bringing the history of weather to the forefront. My name is Pat Hyland, Vice Chair for the National Weather Museum and Science Center. Today’s episode: “Lightning.”
Did you know that approximately 100 lightning bolts strike the Earth’s surface every second? That amounts to almost eight million lightning strikes per day, and three billion lightning strikes each year! Did you also know that lightning is about 50,000 degrees Fahrenheit, or five times hotter than the surface of the Sun?
Lightning is one of the oldest observed natural phenomena on Earth, yet atmospheric physicists and meteorologists alike have grappled for years regarding the mechanisms by which clouds become electrified in order to produce these sparks of electricity that can rocket through the atmosphere at 186,000 miles per second.
With the lightning process being so quick, it takes special equipment to capture what our eyes can’t see. High-speed imaging cameras, like the National Geographic Big Kahuna lightning camera that’s located at the National Weather Museum and Science Center in Norman, Oklahoma, have been and continue to be used around the world to slow the lightning process down enough to analyze the intricate details of this captivating weather hazard.
Today, we are joined by Dr. Vanna Chmielewski, Research Scientist with OU-CIMMS and NOAA-NSSL. Our own Dr. Elizabeth Smith spoke with Dr. Chmielewski to learn more about this fascinating weather phenomenon and her career as a lightning researcher.
Dr. Elizabeth Smith: First, can you tell us briefly who you are, and what you do?
Dr. Vanna Chmielewski: I am Dr. Vanna Chmielewski. I am a Research Scientist here at the University of Oklahoma Cooperative Institute for Mesoscale Meteorological Studies (OU-CIMMS) and National Severe Storms Laboratory (NSSL), and I study lightning.
ES: How does a storm produce lightning?
VC: First we need differently sized ice particles — ice crystals and graupel — which are low-density, frozen droplets. When they collide and separate in the right environments — where there is some liquid water, but it’s below freezing — they also separate charge. The particles fall differently in the cloud, so they carry the separated charge to different parts of the cloud. Eventually, so much charge builds up that there’s electrical breakdown starts between two areas of opposite charge, just like a spark. After the spark gets started, it continues growing and branching, in what we call lightning channels, that can move through the cloud, through air, or to the ground until it runs out of energy.
ES: So why do we observe and study lightning?
VC: Well there are two big reasons that we want to observe and study lightning. The first is lightning, itself, is hazardous. The second is lightning can tell us a lot about how the storm itself is changing. So as a storm updraft becomes stronger — so your storm is getting bigger — it also produces more lightning. We can use lightning to help us monitor which storms are going to intensify, and maybe produce severe weather. We study it because there is still so much about lightning that we do not understand! We don’t know how a flash really starts. We don’t know what it tells us about how ice is growing in the cloud, and also we want to know if we can predict which storms will be producing lightning in the future, or when a storm is going to stop producing lightning and we can resume outdoor activities safely.
ES: National Weather Museum fact: We actually have a pretty interesting lightning camera exhibit in the Museum! Tim Samaras, who was an engineer, well-known in the meteorological community for his tornado research and lightning photography, actually operated the camera that we have in the Museum for a while as part of his lightning research. As folks in our community may well know, Tim Samaras, his son Paul Samaras, and Carl Young tragically lost their lives in the El Reno tornado on May 31st, 2013. After that, the camera spent some time at the University of Oklahoma before eventually coming to our Museum with some gracious support to display it and share Tim’s love for weather and in particular lightning. It’s a pretty amazing piece of equipment that we really do love to show off.
Can you help us understand why high speed lightning photography — like what this camera was used for — is important?
VC: We know that lightning channels develop extremely quickly. Lightning is very fast; normally it’s over by the time you blink your eyes. The lightning channel itself can grow at a rate of 100 kilometers or roughly 62 miles in a single second. So in order to understand what’s really happening within lightning, you need to be able to take a really high-speed measurement to see how it’s developing. Photography itself is really important for understanding lightning, especially when it’s outside of the cloud — the way that our eyes would see it — and so many lightning researchers use that to sort of contextualize the other observations we get, and also to get that high-speed measurement. So we can use the high-speed video to investigate how quickly the lightning channels are growing, when and where the lightning itself produces light, how lightning makes that connection to ground, and then also how lightning itself branches — so where do we expect it to branch and how does that develop. There are two sides to every lightning flash; the one that’s going towards positive charge and the one that is being attracted towards the negative charge. And because of how electrons move through the air, the two sides of a lightning flash actually behave pretty differently, and high-speed-lightning photography has really helped us understand how that is happening.
ES: What is lightning research focusing on these days?
VC: So we have a brand-new lightning measurement that’s being taken from space from the Geostationary Lightning Mapper (GLM), so it’s a really exciting time to be studying lightning! It’s monitoring all the optical emissions of lightning which make it up to the satellite, similar to what you would see with the camera — it is, however, not high speed — so we are learning a lot about what lightning looks like over North and South America and the surrounding oceans. We can see more lightning in hurricanes offshore than we could before. We can also see how large of an area a flash can cover — so the world record for the longest flash was just broken recently by a flash that was over 400 miles long! The previous world record was about 200 miles long and it was right here in Oklahoma. The new observations also bring up a lot of interesting science questions. How much lightning produces light that you can see from space? Is there lightning that’s not actually producing enough light that we can see? How does that compare to other measurements of lightning we have — like what you would see when you turn on the TV and you see there was a lightning flash here — how does that compare?
ES: Can you tell us a bit about the work you’re doing in lightning?
VC: So, we have another exciting tool for monitoring lightning called a Lightning Mapping Array (LMA) right here in Oklahoma. It triangulates the emissions from lightning channels in radio frequencies. As a fun side note, you can use this principle to monitor lightning yourself! If you have access to a physical radio — not a streaming radio through your computer — tune it to an AM radio channel station and you will hear little blips of static whenever there is a lightning flash nearby! We end up using some high-quality timing measurements and a lot of trigonometry, and we triangulate where exactly in the cloud the lightning flash was. So we can tell how high above the ground it was and what area it traveled through. I work with this tool to study how charge arranges itself in the cloud itself. So that’s important for understanding when we expect a storm to produce a lot of little flashes that are really high up in the cloud or whether we expect a storm to produce a lot of lightning that actually makes it to ground and is impacting us here on the ground and our outdoor activities that we might be a part of. So I’m using some of the principles that I’ve learned there to see if we can better predict when storms in a forecast model will produce a lot of these cloud-to-ground strikes hours before the lightning actually happens! We’re also working on a mobile version of a Lightning Mapping Array (LMA) that we can take out to study storms in other areas outside of Oklahoma.
ES: Lightning is a really dangerous thing and it is a leading cause of weather-related fatalities. As of the beginning of October — this year, 2020 — already 15 people have been killed by lightning in the United States. How can people stay safe when the lightning threatens?
VC: The easiest thing to remember when lightning is threatening is “When thunder roars, Go indoors.” If you can hear thunder, you are probably close enough to the storm for lightning to strike near you, so you don’t wait until it is raining, if you can hear the thunder, go indoors! The best shelter you can take is inside a building — just don’t hold on to something that is plugged into an outlet or take a shower. If lightning does strike near the house, the current can travel through plumbing and electrical wires. If you cannot make it into a building, a regular, metal-topped car is a good choice. The car acts as a Faraday Cage, meaning it is a giant, conductive, hollow box. So if lightning strikes the car, most of the current will travel around the outside of the box — in this case, the car — and whatever is inside the box will be safe, as long as you aren’t touching that exterior metal.
ES: Thank you for this very enlightening chat about lightning (had to say it)! We always also like to learn a little bit about our guests, so can you tell us a little bit about what got you into meteorology?
VC: It’s hard thing for me to pinpoint any one specific thing that got me into meteorology. I was born in Ft. Smith, Arkansas and my family moved to Keller, Texas when I was ten, so I spent a lot of time in Tornado Alley, and I’m pretty used to paying attention to weather during tornado season! I have memories as a kid of giving anyone inside “weather updates” after stepping outside, so I’d run back inside “It’s getting colder”, “The wind is blowing”. So I certainly was always interested in paying attention to weather, but I was interested in a lot of other things too! From animals, to garbage trucks, to music, astronomy, food. If you asked me what I wanted to be when I grew up I had a different answer every month. In high school, I realized I was really interested in science, and one of the things I was really curious about was how snow and ice crystals form. So I decided to go on and study meteorology! My plan at the time was to become a forecaster. I had no idea that there were people who studied lightning, or that lightning depended on how those snow and ice crystals were growing inside the cloud. We had a guest speaker come to our school and talk about the lightning research he did, and I was completely fascinated and wanted to learn more. So, now here I am after getting a Ph.D. and I’m still learning more about lightning every day.
ES: It also so happens that you are our first female guest on our podcast, so thank you for joining us! This is an important note, actually, we know that historically there haven’t been very many women in science or meteorology. Can you tell us a little bit about your experience as a woman in science?
VC: It can be a challenge at times. I’m not going to pretend it’s not, but I’m also not the only woman in science and in meteorology, and building those connections with other women has made it a lot easier to deal with the challenges that do happen. During undergraduate school when I was pursuing my bachelor’s degree, I was lucky that my class was pretty evenly split, so I was able to establish connections with other female peers who were also interested in meteorology. We did only have one female faculty, though! When I went on to pursue my Ph.D., there were fewer females in my peer group. I went to a small graduate program. There were seven people in my class, only two of us were women. There was only one in the class the next year, so very few females, and, again, only one woman faculty member. At times it could feel pretty lonely, but I knew I had those connections I had made previously that I could rely on, even if we weren’t all together in the same spot, and I continued to try to make more of those connections! There were, of course, some positive sides, too. Going out doing field work or traveling for conferences, I was often pretty sure I’d be able to have my own hotel room while everyone else had to share! I’m lucky to have great women that I work with here now in Norman, including my boss, my boss is also a woman.
The more interesting interactions I’ve had as a woman in science are often when I’m working outside the office. I’ve done a good amount of field work and maintenance on instruments out in the field, which means driving around large vehicles, carrying ladders, using power tools, and people will let you know that they are not who you expect to see doing the work you are doing! I’ll never forget being told by one of the managers we were working with when I was working on a station that he “wished he saw more young women who knew how to use tools.” I really had no idea how to respond to that, and I still can’t say that I have any idea how to respond to that either, but they will let you know that you’re not following their expected norm.
ES: Thank you, Vanna, for joining us on this episode. Remember, When thunder roars, Go indoors, and you can visit ready.gov to learn more!
VC: Thank you for having me.
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PH: Have an idea for our next episode? Share your ideas and questions for us at info, that’s i-n-f-o, at National Weather Museum dot com [info@nationalweathermuseum.com], or find us on social media. The National Weather Museum and Science Center is a 501(c)(3) non-profit organization that operates with the generous support of people like you. Help us continue to preserve the history and highlight the future of weather research by donating or becoming a member today. Find out more at www.nationalweathermuseum.com
We’ll see you next time for our latest episode of “When Did the Storm Begin” as we bring the history of weather to the forefront.
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