June is Lightning Safety Awareness Month. Lightning is the number two killer of severe weather. Flooding is number one. A lot of people think if it is sunny or maybe just a few clouds around and you hear thunder, it is okay to stay outside until you actually see the lightning. That is not true. If you hear thunder when you are outside, that means that lightning is close enough to strike you!



On Thursday, June 23, chat experts Dr. Richard Blakeslee and Dr. Monte Bateman answered your questions about lightning safety, the global distribution and frequency of lightning occurrence as well as some of its physical characteristic, the relationship of lightning to severe storms and weather (e.g., lightning rate changes may serve as a "pre-cursor" or advanced indicator to later severe weather at the ground such as tornadoes), and other lightning research topics such as lightning-hurricane relationships and terrestrial gamma ray burst.



Bios: Chat Experts Dr. Richard Blakeslee and Dr. Monte Bateman



Chat Transcript



Richard_and_Monte: Hi everyone, we're putting together a few last-minute chat details. We'll be starting the chat at the top of the hour. Looking forward to your questions!



Umm_Matthew: My 5 1/2 year old son wants to know "How does lightning stop" and "How does lightning strike the earth?"



Richard_and_Monte: It stops when it runs out of charge! When a cloud gets an excess of charge, it overcomes the air's insulative ability. Too much charge, the air can't insulate anymore and it breaks down.



Terri: You may already be planning to do this, but can you explain exactly what lightening is and a little about how it works.



Richard_and_Monte: In very simple terms, it's a large electric spark. The way natural lightning works is when the voltage in the cloud becomes large enough, you get a breakdown process initiated. The charge descends from the cloud to the ground in steps until it gets close to the ground. At that point, objects on the ground respond to the high electric field and launch their own upward streamers. These are like weak sparks. Then one of them will connect to the downward leader, and that completes the circuit. Earth responds with a very high current wave, which is the bright flash that we see.



curiosity: hello scientists and everyone!



Richard_and_Monte: Greetings. :)



Terri: I live in southern Florida. It seems to me that there is less lightening this year.



Richard_and_Monte: As you probably know, Florida is the lightning capital of the U.S. So, what you're perceiving is probably just the law of averages. Over long terms, Florida is still the winner in the U.S. Lightning is caused by convection, and seasonal variations in convection will directly affect the amount of lightning you see.



Umm_Matthew: What creates the charge in the air?



Richard_and_Monte: This is a very good question - we're currently doing research on this. Charge isn't created, it's separated. The best candidate charging mechanism is the interaction of ice crystals and small hail particles in the presence of liquid water. The real question we don't understand is why - we've seen this happen in the lab and in the clouds, and we don't really understand why, at an atomic level.



SkyGirly: Why is there lightning in the air?



Richard_and_Monte: Can you elaborate? Would like to answer your question!



curiosity: Like it mentions in introduction, lighting can help to predicate the severity level of storms. How it done?



Richard_and_Monte: Primarily by monitoring the rate of lightning flashes and as it increases, we've come to understand that this is a good signal for upcoming severe weather.



zmarcone: Can you explain what happens to nitrogen in the air when lightning strikes?



Richard_and_Monte: Sure - the air "gets burned" or oxidized. Nitrogen combines with oxygen and then comes down with the rain. It's called nitrogen fixation, and that becomes fertilizer. Many atmospheric scientists study nitrogen oxides and their contribution to air pollution. Lightning is the largest natural source of these oxides.



zmarcone: Is there a difference between lightning on Earth and on other planets?



Richard_and_Monte: We don't *think* so. Obviously it will exist in an atmosphere with a different chemistry, so there may be differences in color, etc. But there's not much known about lightning on other planets, other than we know it exists.



Nowiser: Is it possible to create artificial lightning? And could it ever be used as a precision strike weapon in conflicts?



Richard_and_Monte: We call that triggered lightning, where we trigger that from a cloud. (Model rockets that trail wires can trigger lighting, under some circumstances.) Triggered lightning is a useful research tool for studying lightning, and we're using it right now.



Pesh_Ant: If lightening storm strikes while I'm in an open field, what do you recommend is the safest alternative? Taking shoes off for example?



Richard_and_Monte: The first thing to do is get indoors into a significant structure or vehicle - if at all possible. If not, don't be under a lone tree; if there are several people, don't stand together because it could strike the whole group! Being in a forest or cluster of trees is better than an open field or open water. But again, best to be indoors. If you're caught in a field, be as low as possible and as little contact with the ground - but again, head for shelter or trees!



Terri: Can we suppose that there is less likelihood of tropical storm because of the decrease?



Richard_and_Monte: The decrease of...?



200tamara: What kind of flash in FLORIDA except cloud-to-ground. Why horizontal?



Richard_and_Monte: Lightning that occurs in a cloud or cloud-to-cloud is called in-cloud lightning. That's the most common. Lightning hitting the ground is called cloud-to-ground or a ground strike.



wvy: What type of monitoring is done on lightning strikes?



Richard_and_Monte: Lots! We have space-based measurement; we have many kinds of ground-based networks that monitor lightning. Some systems can detect lightning globally (although they generally detect mostly cloud-to-ground). Other systems are regional in measurements and can detect all lightning.



Nowiser: Does the sun have any effect on lightning?



Richard_and_Monte: Heating from the sun is the ultimate source of lightning. This heating leads to instability in the air, which in turn leads to the formation of thunderstorms. For this reason, lightning amounts tend to peak in the afternoon, around 4 p.m. local time. With satellite measurements, we can watch it move around the Earth.



Richard_and_Monte: I should also add, lightning can occur at ANY time of the day, not just in the afternoons!



paulh_40: There was a report on nasa's site that gamma rays were observed incoming from a lightning storm it was stated that the cause was from antimatter generated by the lightning is this a widely held theory?



Richard; We are learning that since thunderstorms create large regions of high electric field, they act as natural particle accelerators. Scientists have detected positrons from thunderstorms. In addition, this is a relatively new discovery, but a number of space-based sensors have detected gamma ray bursts from thunderstorms. There are a lot of details yet to be uncovered in trying to fully understand this phenomena.



zmarcone: Is lightning a flow of electrons from a cloud to the ground?



Richard_and_Monte: It's a flow of charge that moves in both directions. Typical cloud-to-cloud flash moves negative charge from the cloud to the ground, although there are some ground strikes that are called positive lightning that move positive charge to the ground. These positive discharges often are very powerful and may lead to forest fires and other damage of property.



questor: When a significant lightning strike occurs, what is the typical temperature that the air immediately around it can be heated to? Also, what sort of voltages are we dealing with? (Maybe I don't want to know!)



Richard_and_Monte: Lightning on average is 30,000 Kelvin. The sun's surface is about 6,000 Kelvin - so five times as hot as the sun's surface!



Pesh_Ant: Do solar flares effect lightening and storms?



Richard_and_Monte: They're a source of charged particles in the atmosphere, so if a storm was in progress and ingested those particles, would likely affect the lightning. But, don't know of any measurements that establish this speculation.



Umm_Matthew: What other planets have lighting?



Richard_and_Monte: Jupiter and Venus that we know of from observation. Saturn, possibly.



paulh_40: How many amps of current flow are involved in a discharge?



Richard_and_Monte: A large lightning flash can have 100,000 amps, which is about 1,000 times more than an average arc welder.



Terri: Yes I know at the moment but I am talking about the number of tropical storms. Also I am trying to understand your explanation of charge created vs. separated.



Richard_and_Monte: Atoms have positive and negative charges, so neutral in natural state. If you remove electrons - negative - from an atom, it's left positive. Those freed electrons attach to other atoms, leaving them negative. In the charged separation process, in which small ice particles are colliding with hail, there's a separation of charge which leaves the ice crystals positively charged and the hail negatively charged. Small particles are carried up by the updraft and the hail falls out, causing a large-scale charge separation in the thunderstorm. We didn't create charge - just separated it and moved it around - so the cloud is still net-neutral.



shanwin: I've heard that a person is completely safe from a lightning strike while inside of a car. Is that true, and if so, how can that be possible?



Richard_and_Monte: If the car is metallic - not a convertible! - then a person is shielded by the metal of the car and lightning would be safely conducted around the people inside. This has nothing to do with the rubber tires! This is know in physics as a "Faraday cage."



gfinley: Do you think we'll ever be able to harness and store the energy in lightning? Are there any current experiments to that end?



Richard_and_Monte: Each cloud-to-ground flash transfers about 1 billion joules of energy. On average, there are about 100 flashes per second, globally. If ALL this power could be captured, it would be around 1 trillion watts. However, there are 2 as yet unsolved problems: (1) most of the power is converted to thunder, hot air, and radio waves, which cannot at present be captured, leaving only a small fraction of the power to be captured and stored by a lightning rod, and (2) we would have to cover our land surface with tall towers - the cost and other disadvantages far outweigh any small benefit. For example, the amount of energy that you could capture from a single lightning flash would power a 100W light bulb for a few months. Thousands of flashes would have to be captured just to power a small home. - from Uman's book, "The Lightning Discharge."



Nowiser: How is Thunder created?



Richard_and_Monte: When the many thousands of amp of current flow through the air, it becomes super-heated and expands rapidly, producing a shock wave that we hear as thunder. Lightning has kinks and turns in it, and that's what causes thunder to rumble, instead of just one big boom. If it's extensive lightning, thunder can rumble from several seconds (5-30, in general).



terraform: Hello from Ottawa, Canada. in photographs I have taken (from indoors), I have seen several lightning strokes following almost the same shaped path but displaced a bit. In one photo set it seemed that the path shifted over the period of several hundred milliseconds. Is it possible that the windy conditions caused the path to shift between strokes?



Richard_and_Monte: That's exactly what's happened - good eye. The lightning channel blows with the wind. You can also get this affect by panning your camera with the shutter open. Lightning typically occurs in multiple strokes, and each one follows essentially the same path of the previous stroke - an ionized trail. In the photo, it's the ionized trail that's being blown between strokes.



Rachel: Does the nitrogen travel in the lightning or is it in the surrounding atmosphere when it oxidizes?



Richard_and_Monte: It's everywhere in the atmosphere (78% nitrogen in the Earth's atmosphere). It doesn't travel in the lighting - the lightning travels in the air.



Terri: Your explanation to Zmarcone, kind of like an air bbq ;-)



Richard_and_Monte: That's true. :) You don't want to be hit, or you'll be BBQ!



curiosity: What is a terrestrial gamma ray burst?



Richard_and_Monte: We're not sure what causes it - it seems to be associated to strong thunderstorms. It's a by-product of the natural particle accelerator that is created by the large fields in the thunderstorms.



M_Miziorko: Returning to the nitrogen issue for a moment, is there research currently ongoing to create a method to quantify the amount of nitrogen released in a lightning strike or thunderstorm?



Richard_and_Monte: There are a number of scientists who are attempting to measure the amounts of nitrogen oxides produced by lightning.



erjet: How do you explain the very increased number of lightning storms happening this few last years, especially this year? And here in Albania for example we had about 2 weeks ago a lot of them , few night every few seconds for at least 2-3 hours.



Richard_and_Monte: Thanks for joining us from Albania! It's just a climate association - there are highs and lows depending on the year. Globally, there are large-scale teleconnections in the development of weather. Example that many have heard of is El Nino, which has strong affects on location and severity of weather (hurricanes, droughts, large snow events, etc.)



Jamie: How hard is it to trigger lighting?



Richard_and_Monte: It's easy if you know how. :) Seriously, you need a rocket that can move faster than about 10 meters/second, or 20 mph, trailing a wire. The key is launching the rocket when the electric field is high enough at the ground. (That means it's high enough in the cloud.) Obviously you need to be inside of a Faraday cage when launching this rocket - this is very dangerous. In other words, don't try this at home! When researchers trigger lightning, they typically do this in a very controlled environment so people don't get hurt.



Pesh_Ant: Awesome question Nowiser!



Richard_and_Monte: Agreed!



Tim: If lightning is over so quickly, why does thunder sometimes go for several seconds?



Richard_and_Monte: Because light moves faster than sound. The length of the sound has to do with the length of the channel. Speed of light is 186,000 miles/hour, speed of sound is 0.2 miles/hour.



Farouk: Is it true that the lightening strike passes through the air at a very high speed (speed of light) causing it to be an ionized plasma and that's why we could see it ??



Richard_and_Monte: It does pass through the air at a very high speed -the high current pulse we call the return stroke travels up the channel at about 1/3 the speed of light. The light is created by the heating of the high current.



paulh_40: Has ball lighting ever been observed close up?



Richard_and_Monte: Ball lightning is mobile plasma spheres that are rare and unpredictable - makes it very hard to study. Yes, it's been observed up close, but few measurements have been made.



gannon12: Did you know about lightning producing antimatter b4 you launched the satellite that detected it?



Richard_and_Monte: The NASA BATSE experiment first discovered terrestrial gamma ray burst, and they were surprised to see gamma rays coming from Earth, as these are usually produced by the collapse of a star or other astronomical events. More about BATSE: http://gammaray.msfc.nasa.gov/batse/. The PI for BATSE, Jerry Fishman, was just awarded the Shaw Award for all the discoveries related to his work in this area.



Steve: Do new thunderstorms generally produce CC lightning before CG?



Richard_and_Monte: Typically in-cloud happens first, by about five minutes. BUT, sometimes, the first discharge is cloud-to-ground lightning - and this can be very dangerous.



Terri: Less likelihood of tropical storm because of the decrease in lightening strikes I have noticed this season?



Richard_and_Monte: The lightning isn't the driver - it's a consequence of the convection. Large-scale climate factors really determine the likelihood of tropical storms.



coldfiresidhu: On average what amount of voltage is present in an average lightning and what was the maximum voltage recorded?



Richard_and_Monte: It's not the voltage, but the current. You can have millions of volts inside of a cloud, or between the cloud and ground.



Robe: Do you know of any projects in progress that are towards harnessing the power of lightening for long term storage for electrical needs? Due to the high current capacity of a lightning bolt, one would think that if you were able to achieve long term storage of said bolt that it would go a long ways towards solving the electrical needs of the local population.



Richard_and_Monte: Each cloud-to-ground flash transfers about 1 billion joules of energy. On average, there are about 100 flashes per second, globally. If ALL this power could be captured, it would be around 1 trillion watts. However, there are 2 as yet unsolved problems: (1) most of the power is converted to thunder, hot air, and radio waves, which cannot at present be captured, leaving only a small fraction of the power to be captured and stored by a lightning rod, and (2) we would have to cover our land surface with tall towers - the cost and other disadvantages far outweigh any small benefit. For example, the amount of energy that you could capture from a single lightning flash would power a 100W light bulb for a few months. Thousands of flashes would have to be captured just to power a small home. - from Uman's book, "The Lightning Discharge."



Faisal: Can't lightning's power be used(redirected for example)? or preserved at least?



Richard_and_Monte: No. The Earth has a fair weather current of about 1000 amps. But this is "spread out" over the whole surface of the planet - a very big place! That works out to about one-one-trillionth of an amp per square meter. So, if you could build a 100% effective collector (we can't), you would need a collector the size of Nevada to collect 1A. That's about the amount of current from 2 D-cell batteries.



Raw: Is it true that lightening helping create Ozone....maybe that's the way our planet heal...or trying to do so? Can we connect the ozone layer holes with stronger lightning appearance?



Richard_and_Monte: Lightning will produce ozone, but there's no connection between lightning and the ozone layer. The ozone created by lightning can't make it to the higher parts of the atmosphere where the ozone layer is.



paulh_40: I have read reports about ball lightening passing through the walls of a plane why did it not spread over the skin of the plane and lose its shape what keeps it together is it bipolar.



Richard_and_Monte: Ball lightning is a puzzle - it occurs in a lot of different forms.



UmmHumza: Does the different types of lightening (ground flashes, cloud to ground lightning, cloud flashes, etc) have anything to do with the intensity of a storm?



Richard_and_Monte: Yes, it takes more energy to create a negative ground flash than a cloud flash, and takes even more energy to create a positive ground flash. Very strong storms produce much higher lightning rates and often a much higher proportion of that lightning is inter-cloud.



Umm_Matthew: What is cloud seeding?



Richard_and_Monte: Cloud seeding is when you sprinkle a salt into a cloud - the salt has a crystal structure similar to ice and is supposed to cause condensation followed by rain. Unfortunately, you often get snow or hail instead. So the snow evaporates before it hits the ground, and the hail damages the crop you were trying to aid.



Isaac: Why does Google Weather's thunderstorm icon feature red lightning? Artistic license, real phenomenon, or terrible omen?



Richard_and_Monte: Oh yes, red lightning is real - same as red sunsets. It's a scattering of the light through the rain shaft, etc.



Marie_Dovale: Hi! I want to know why the lightning has too many branches?? And what influence that it occurs in one place or another?



Richard_and_Monte: It's caused by the initial leader which comes down from the cloud as a series of steps, and at times breaks into multiple paths. For typical cloud-to-ground lightning the branching happens downward and for lightning that's sometimes initiated from tall towers or mountain, the branching occurs upward. Only the first return stroke will be branched - subsequent strokes will follow the primary channel to the ground.



Terri: But lightning strikes (as I have noticed) are usually afternoon and early evening. Why is that?



Richard_and_Monte: It's the product of convection, driven by solar heating, and max heating occurs in the afternoon and early evening (peak 4 p.m. local time).



johnawad: What's a "stepped leader"?



Richard_and_Monte: A leader is an initial breakdown of the air caused by high fields. It moves to the ground in steps, or short segments, about 50 meters per step.



Mike: Does lighting ever hit the same location again?



Richard_and_Monte: Absolutely. Especially tall buildings and towers - they can be struck often (think Empire State Building).



curiosity: The gamma burst is so absorbed by atmosphere?



Richard_and_Monte: Yes, but they are clearly strong enough to be detected in space, so not totally absorbed.



rilke: How are people able to survive lightning strikes if they're so hot and powerful?



Richard_and_Monte: Lightning kills by stopping your heart, and if you're lucky enough that it passes on the outside and not through your heart, you can survive a lightning strike. Many have, though they are badly injured. Sometimes you're not part of the flash itself, but a side flash - and that's enough to cause injury.



gannon12: I heard people talk about a "lightning line" is there such a thing?



Richard_and_Monte: We've never heard of this term - can you elaborate?



jjeam: So why is Florida so prone to lighting more than other states.



Richard_and_Monte: Because it's in a very warm part of Earth, and very humid - two coastlines that are very close together, causing interaction between sea breeze and land breeze every day. Plenty of moisture.



zmarcone: What is the maximum distance lightning can travel?



Richard_and_Monte: We're assuming lightning outside a cloud - it can go 10s of kilometers. Inside a storm systems, it's been observed to go hundreds of kilometers.



OceanicCactus: Tucson, Arizona here!



Richard_and_Monte: Welcome, Tucson!



sonic: Hello from London!! : ) Is it possible to predict the time between lightning strikes during a thunderstorm? (and the direction of the next lightning strike- does it ever follow a pattern?)



Richard_and_Monte: Hi London! No, you can't predict either of these. Wish we could...



Pesh_Ant: Sometimes I'm afraid to use my cell phone near a window during a storm. Based on the Faraday Cage you just mentioned, can a cell phone be used after a car has been hit with lightening? I met a guy on the Appalachian trail who's been hit twice by lightening. He goes by the name of lightening, no joke.



Richard_and_Monte: Indoors, a cell phone is safe to use. in the car, it's safe whether it's been struck by lightning or not. Tell "Lightning" to seek some shelter, the next time you see him!



(Moderator Jason): With all these great questions, we're going to keep answering them for another 10 minutes or so...



Nowiser: I have seen photographs of lightning striking when a volcano erupts why is this?



Richard_and_Monte: Volcanoes release lots of hot gas and water vapor as well as lots of dust. The heat causes convection and significant charging. We don't know how much this relates to a typical thunderstorm, but in the past few years, lightning mapper systems have been placed around volcanoes in Alaska and South America and Iceland to try to learn more about it.



gannon12: I was sitting next to my uncle during a storm one day and lightning struck very close by. We both could taste copper in our mouths like sucking on a penny my uncle described it. what would cause this?



Richard_and_Monte: Interesting. Were you inside or outside, like on a porch?



Farouk: Why when we wanna calculate the distance between us and a lightning strike: we count the seconds between the flash and the sound and then we divide these seconds by five to find the distance in miles ??



Richard_and_Monte: It's because of the speed of sound vs. the speed of light. Sound travels at one mile per five seconds. Light is essentially instant.



Nowiser: Where I live in Washington State near Portland Oregon we never have lightning why is this?



Richard_and_Monte: You don't have the same levels of convection or heating compared to, say, Florida. Also, the ocean is colder and keeps the air cold.



johnawad: Has lightning ever struck a space shuttle during liftoff ?



Richard_and_Monte: No, but it has hit the pad while the Shuttle was on it. KSC has lots of effective lightning protection around the launch pads. Apollo 12 was struck by lightning on launch, though. It actually triggered the event. The mission proceeded without problems.



hdfsg: This is very interesting. I'm a farmer and am always outside during thunderstorms, we have had some pretty severe ones this year in western ny. If I got struck on an all terrain vehicle like a 4 wheeler, with rubber tires, and rubber boots on, what would happen?



Richard_and_Monte: Wow, you'd melt! You'd need to be inside of a metal cage. The rubber tires and rubber boots won't help you.



kellycosas: What is the safest position to get into should you get caught out in an electrical storm? Years ago, I heard lie flat, now I hear that you should squat in a small ball, arms around legs, forehead on knees, perched on one leg away from the tallest trees and ridge lines. I hear this is the shortest path for the lightening to travel?



Richard_and_Monte: Indoors is the safest position! But if you're truly stuck - you want minimal ground contact because step voltage across the ground is dangerous. Cows get killed because they can't put their feet together, for example. So put your feet together so voltage can't travel. But again - get inside. There's really no place remotely safe outside in a lightning event.



Chris: What are some of the factors that determine the color of lightning? While most lightning I've seen is white, I have also had the pleasure of witnessing a storm that had very bright and distinct red lightning.



Richard_and_Monte: Colors occur due to scattering of light. So in the distance, you might see red just like red sunsets.



Jack: I believe you mean speed of light is 186,000 miles per second.



Richard_and_Monte: Yes, thank you. :)



Terri: Ball Lightning, how big are they?



Richard_and_Monte: They can be from marble size to beach ball size.



Pesh_Ant: Thank You for answering our questions!



Richard_and_Monte: You're very welcome - these are terrific questions.



gannon12: What happens the lightning strikes water?



Richard_and_Monte: It spreads out, just like on the ground. It can kill fish, but typically doesn't penetrate very deeply.



Pesh_Ant: Does the increase in Carbon Dioxide in the atmosphere effect storms or lightening? This is in conjunction with erjet's question.



Richard_and_Monte: No, there's no documented effect at this point.



jordan: How dangerous can lighting be to aircraft? In particular passenger jets?



Richard_and_Monte: On average, every passenger airliner triggers lightning once a year, usually on take-off or landing, and survives quite nicely!



(Moderator Jason): We've got time for a few last questions...



Rasha: Hi, I'm an student in engineering and found this to be very interesting!



Richard_and_Monte: Thank you very much - we've enjoyed it!



gannon12: Is there such a thing as heat lightning?



Richard_and_Monte: Yes, there is. It's regular lightning that occurs too far away to hear thunder. This typically happens in the summer, hence the term heat lightning. Sometimes distant heat lighting can also be called "sheet lightning." Remember when we talked earlier about the lightning that blows in the wind? Some people call that ribbon lighting.



xeaphyr: Since airplanes are faraday cages, the people inside would be safe from lightning in a thunderstorm, right? However, does the lightning affect the electronics/equipment of the airplane in any way, or are those protected by the cage as well?



Richard_and_Monte: Yes, electronics on a plane can be damaged. Most aircraft that are metallic are safe.



gannon12: Yes we were on the porch. it struck a fence row like 30 feet from us.



Richard_and_Monte: It might have been that if the fence was metal, it might have vaporized some of the material, then those ions blew toward you.



johnawad: Where's Jason? He's always saying something and encouraging us to ask! :P



Richard_and_Monte: He's here and busy behind the scenes. He says hi. :)



Jack: Is there a way to visually distinguish a positive lightning strike from a negative lightning strike?



Richard_and_Monte: No. You can measure it, but not visually.



gannon12: They say lightning travels in a line relative to the storm called the lightning line. heard it from a weatherman once.



Richard_and_Monte: We've never heard that term. Very interesting!



Pamela: We get a lot of lightning storms here in Glasgow, Scotland, but it's hardly a warm climate, so no idea why!



Richard_and_Monte: Greetings, Scotland! Not warm, but you get "orographic lifting" - that's when the wind hits the cliffs and is pushed up. Of course, you have plenty of moisture! :)



Nowiser: Do you enjoy Lightning Storms?



Richard_and_Monte: We LOVE them. They're very beautiful.



dhanelin: Middle School student from Massachusetts! Does lightning only occur in cumulonimbus clouds??



Richard_and_Monte: No, it can happen in many types of clouds - nimbostratus, for example. But cumulonimbus are the largest producers. (Welcome, Massachusetts! Study hard!)



shanwin: Can lightning strike through windows? Wouldn't this make a car a little unsafe from lightning?



Richard_and_Monte: It won't strike through a car window. Only will strike through a house window if there's something giving it a path (wires, etc.)



200tamara: Thank you!



Richard_and_Monte: Very welcome!



johnawad: I want to thank Jason behinds the scenes for his great job! He's always supporting during chats. Thank you Jason! :)



Richard_and_Monte: Three cheers for Jason!



(Moderator Jason): Thanks :) Happy to help...



jordan: Thank you for your time, interactive events like this are really interesting!



Richard_and_Monte: We enjoy them - appreciate these great questions and your participation!



Jack: Yes, thanks Dr. Richard, Dr. Monte (and others behind the scenes) for taking the time to do this. It has been quite useful.



Richard_and_Monte: We thank you all.



(Moderator Jason): Thanks for joining us tonight. We've had some great questions. And a big thanks for Richard for sitting down with us. We'll have a transcript up in a few days. For more chats, please keep an eye on http://www.nasa.gov/connect/chat - Thanks again for participating.



zethaaron: I've heard of "thunder snow" as in a snow storm producing lightning, though I've never seen one (by the way I live in Canada with plenty of snow), is it simply that snow falls slower than rain and doesn't produce enough static electricity to be a common phenomenon?



Richard_and_Monte: Okay, one more question! It's unusual because there's not lots of liquid water in a snowstorm. But snowflakes are very efficient at separating charge. There were several thundersnow storm this past winter all around the country. The thunder sounds different in a thunder snowstorm because the air is cold and dense.



End chat transcript