Weather Guard Lightning Tech

AEM Lightning Expert on Severe Weather Risks for Wind Farms

This episode features an insightful discussion with Dr. Elizabeth DiGangi, a Lightning Scientist at AEM, who shares her expertise on severe weather patterns, the findings of the AEM 2023 United States Lightning Report, and the potential impact of storms on wind turbines. Dr. DiGangi provides valuable insights into the formation of tornadoes, hail, and lightning, as well as the measures wind farm operators can take to mitigate risks associated with severe weather. Reach out at  https://aem.eco/contact-us/ !

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Allen Hall: Welcome to the Uptime Wind Energy Podcast, your go to podcast for the latest insights and discussions on the wind energy industry. I’m your host, Allen Hall, along with my co host, Joel Saxum. The U. S. Heartland has recently experienced a series of severe weather events, including violent tornadoes, intense lightning strikes, and large hail.

These extreme conditions pose significant challenges to the wind energy industry, as wind turbines are particularly vulnerable to the forces of nature. We are thrilled to have with us a very special guest, Dr. Elizabeth DiGangi a Lightning Scientist at AEM, and AEM is based in Germantown, Maryland. Dr. DiGangi holds a Doctor of Philosophy in Meteorology from the University of Oklahoma. bringing a wealth of knowledge and expertise to our discussion. In this episode, Dr. Daganji will share her insights on the recent severe weather patterns, the findings of the AEM 2023 United States lightning report, and the potential impact of these storms can have on wind turbines.

She will also discuss the measures wind farm operators can take to mitigate the risks associated with severe weather and ensure the longevity and efficiency of their turbines. Turbines, whether you’re a wind energy professional, a meteorology enthusiast, or simply interested in the intersection of weather and renewable energy.

This episode promises to be both informative and engaging. Join us as we explore the challenges and opportunities presented by severe weather with the wind energy industry with Dr. Elizabeth DiGangi from AEM, Dr. DiGangi. Welcome.

Dr. Elizabeth DiGangi: Thank you very much. I’m happy to be here.

Allen Hall: You’ve come at a really good time in a sense and also a really bad time is that there’s been so much Horrible weather in the middle of the united states where most of the wind energy is created tornado after tornado and the storm chasers Have been putting a lot of that up on youtube and some of them saw 10 11 tornadoes in an afternoon It looks like movies What drives the quantity of tornadoes, like we just saw is that something special about the storm, or is it just a confluence of independent actions?

Dr. Elizabeth DiGangi: It’s something special about the storm environment. Whether or not okay, so to start with, the type of storm that produces a tornado has to have, in almost every case unless you’re getting little, like dust devil equivalents, a storm that is producing a tornado has a rotating updraft. So the air that goes in and up that’s feeding the storm, spins while it goes up.

And that helps the storm achieve what we call a quasi steady state. Like it almost behaves like a spinning solid. If you had a cylinder that you were just twirling. There’s like a similar kind of analogous physics going on. And that helps these storms persist for a long time. Obviously you can either have isolated supercell thunderstorms that produce tornadoes, which are characterized by these rotating updrafts.

These also are the storms that produce the largest hail. They tend to have very strong updrafts and a lot of capacity to like make this severe weather. And then you can also get linear or quasi linear convective systems that get little embedded rotations in them where they can spin up like those are the sort of short term tornadoes that like go for a little bit and they’re like an EF1 or an EF2 tops and then dissipate after five or ten minutes.

But the line might produce more. So those are the two modes that it happens. But when you have an outbreak like this is like a convergence Both like air, like atmospheric convergence in a literal sense and just the convergence of so many factors that optimize the whole, like a whole region for tornado production.

The two big key things are three key things are heat, moisture. lift, there’s a fourth thing, something called wind shear. The heat, moisture, and lift generally are pretty easy to come by in the central plains and of the U. S. In this time of year because you have warmer, moist air from the Gulf of Mexico that kind of comes up into the plains, and then usually that air mass ends up up against a drier, air mass to the further west, like from the mountains and stuff.

And that’s where you get like the term dry line. It’s literally like the line where it goes from being humid to dry. And along the boundaries like that and along warm fronts I think this system was probably had a frontal situation going on because there’s like a larger scale atmospheric flow driving it.

But along these boundaries, that’s where the lift comes in because you get convergence of air near the surface. And it’s warm, and it’s moist, and it’s less dense than the air it’s coming in contact with, so it goes up. The wind shear is the thing that makes it spin. Wind shear is defined is just the way the wind changes with height.

If you have winds coming in from the southeast at the surface, and as you go up through the atmosphere, because the things going on at a high level and a mid level are different than at the surface, the that wind shifts, in a clockwise direction until it is now when you’re up in near the jet stream, the jet streams flowing from west to east.

And that is what primes, that’s what makes it so that the storm can spin because the air is then turning as it goes up along those boundaries.

Allen Hall: It’s how the wind industry works here. The mere fact that wind is that dry air is coming from the west. And, which makes it great for wind turbines, is hitting the Gulf Coast humidity, boom.

That’s where the action gets really violent. And that happens, does that happen only in a particular time of year? You don’t see that in December and January.

Dr. Elizabeth DiGangi: Yeah, and it’s much more typical in springtime. Usually by mid to late June, you get in the U S here, we’ll get like a big high pressure system that kind of sits over the middle of the country and you can get good wind from that too.

It’s just spinning counterclockwise instead of clockwise or clockwise instead of counterclockwise. And the, but that kind of prevents storms from happening during the day. During the summer is when you tend to get those nocturnal systems that happen because you get, can, you get like smaller, weaker storms maybe up in like the high plains and in the mountains and then they flow downhill and as they are moving and night comes on, they merge together and then you get these big convective systems that just cruise across the central and northern plains at night.

It’s just a different convective regime. But springtime is just when the jet stream is in the right spot and there’s that nice dry line set up and you get The right flow off the gulf and everything’s in place.

Allen Hall: That explains a lot. So the thunderstorms we received in August, I lived in Wichita for a number of years.

The thunderstorms you get in August are nothing like the thunderstorms you get in April. They are different animals.

Joel Saxum: The troubling thing here though is for the wind industry is that because of the the taking advantage of the wind, of course, right? There, the wind turbine farms are placed.

In an area that is prone to tornadoes as well, right? Like I was watching this, a meteorologist on Twitter I was watching put out a map of all of these tornado outbreaks. Where all the warnings were, and the tornado warnings, tornado watches, all this stuff. And like the patterns of those, okay, that was weird how homogeneous the patterns were almost like, it was like, you just moved over a little bit and they were in the same exact path all the way from basically Northern Texas to Wisconsin.

But you saw every place they popped up on the map. I was like, Oh, I know wind farms there. Oh, there’s wind farms there too. Oh, there’s a wind farms there too. So you start I started calling, I started legitimately texting my insurance industry friends Hey guys. Be ready for Monday morning, because it’s coming.

Allen Hall: And we should take those alarms that go off, and the sirens that go off, and now you’re getting, receiving texts from systems like AEM produces, that tells you, hey, there’s a tornado in the area you better take action. I know you get a little complacent, especially when we lived in Wichita, weirdly enough, that Tornadoes were so frequent that people would just sit on the patio and watch them go by but that’s a bad rule of thumb, right?

You should not do that. Particularly if you’re in a wind farm, you should get the heck out of there. Those are serious, right?

Dr. Elizabeth DiGangi: If you were like in and around a wind farm when there was a tornado blowing over, that is the, there is a lot of potential very heavy debris that could be slamming into you.

That’s the danger is not necessarily the tornado itself, but what it touches because whatever it touches, it picks up and throws. And I would personally, I have been next to a wind farm during a thunderstorm for good reason. Not a tornadic one though but man, I would not want to be hit by like a flying turbine blade.

Allen Hall: Now let’s talk about the hail bit, because one of the most damaging things to wind turbines not necessarily is tornadoes, but is hail. And Joel in particular has seen a lot of hail damage in his day doing root cause analysis damage on wind turbine blades. Hail comes along with these big storms, and most recently, I’ve seen I’ve seen hail. This spring, that looks like to be the size of cantaloupes, it is massively big. What creates hail of that size?

Dr. Elizabeth DiGangi: Hail forms in a thunderstorm when you get a type of, you basically get an ice particle that grows by accumulating super cooled liquid water. There’s this really cool thing that happens in the middle of thunderstorm. When you get higher up than the zero degrees Celsius level, like the freezing level, there’s something called the mixed phase region where because of all of the like water phase changes happening, things are evaporating, things are melting, things are freezing. There’s a lot of different seat. absorption and release processes.

So you can actually get into this state where there is a mixture of ice particles of different types and super cold liquid water, which is water that is still liquid, but it is sub freezing. And when super cool liquid water hits something, it freezes on contact. So ice particles in the cloud will basically, because they’re being blown around by the wind, collide with super cool liquid water and grow.

So And that’s how you get Gropple, is basically like baby hail. It’s some, it’s a, like a small ish dense ice particle. It’s like a chunk, little chunk of ice little ball. Or, they look more styrofoam peanuts, like packing peanuts. And they will keep growing while they’re accumulating super cool liquid water.

This is really neat because this actually ties into lightning, which this is my specialty by the way. My, my dissertation talks a lot about the relationships between the cloud physics and lightning activity. And one of the storms I studied actually produced five inch hail. So it was it was really cool.

But yeah, those grapple particles are accumulating the super cool liquid water and getting bigger and bigger as they do. They’re just layering ice and any ice crystals that are around that come, that bounce off of them in the meantime, they’ll steal an electron from. And then you get charge is building up in the storm at the same time that these hail particles are growing.

Those two processes are very closely related. Which is why we’ve actually observed in the scientific community in general, that lightning total flash rates are very well correlated with hail. If you get a sudden surge in lightning, you’re probably seeing some hail growth. But the really important thing about how large the hill gets depends on how strong the updraft is.

And those supercells with those really stable rotating updrafts that are very strong they basically will be holding these chunks of ice as they get bigger and bigger. Big as your fist, bigger than that. They are floating in the air because the wind going up is providing enough force to keep them buoyant.

And so the hail will fall out when it becomes too heavy for the updraft. So the storm that I studied in my master’s thesis and my dissertation, the storm that will be mine forever, I’ve decided it was a super snell in Oklahoma, in central Oklahoma in 2012. It produced five inch hail late in its lifetime, early in its lifetime.

We sampled it with multiple mobile radars and some in storm ballooning and stuff. And The updrafts that we calculated from the two radars looking at it at the same time were more than 60 meters per second. So that’s like I think roughly translates to like over a hundred miles an hour.

Allen Hall: Over a hundred miles an hour.

Dr. Elizabeth DiGangi: Yeah. I’m being conservative because I don’t remember the conversion off the top of my head, but it is. Yeah. So that’s like how fast that’s going up. So yeah, that’s what can hold a baseball sized piece of ice. Many of them near that long.

Allen Hall: Alright, so it’s, that’s a really dangerous situation. Again, if there’s hail in the area or the forecast is calling for hail, you need to get out of there.

Particularly Texas, Oklahoma, Kansas, parts of Nebraska, Iowa. The hail can be huge.

Joel Saxum: It makes this, some of this conversation makes I’m having revelations from my whole life right now. I’ll grow up in northern Wisconsin, right? Like, when we get, if you get hail in northern Wisconsin that is the size of A big marble.

People are like, oh my, did you see that hail? Cause we don’t get as, we don’t get as strong of storms up there, right? Just in general. Oddly enough, my high school was called the Hayward Hurricanes. We didn’t have a whole lot of hurricanes in northern Wisconsin. Nope. Yeah, but you talk to people like, oh, that one was, we saw some that were the size of a quarter.

If you see size hail the size of a quarter down in like northern Texas or Oklahoma, they’re like, yeah, just another storm. It’s not a, it’s not that big of a thing, but you do see, yeah, then you see the pictures of people like holding baseball sized hunks of ice.

Allen Hall: Probably one of the bigger killers in weather is lightning, and we just talked about Gropple being the source of that ice particles floating up in the cloud and circulating around, creating charge.

Yeah, that’s a complicated process. We still, I’m tossing it out to you, you’re the expert. I know from the research on the engineering side, we really don’t know how lightning is even created in a cloud. It just happens.

Dr. Elizabeth DiGangi: It’s something that’s still up for investigation in the details of it are up for investigation in the lightning research community.

But the sort of general thing is that when I talked about this charge exchange, I was teasing a little bit there. So when those, all these ice particles are flying around in the cloud and crashing into each other, and it’s, under certain temperature conditions, whatever the exchange electrons between different size and like density particles, and then like those little smaller ice crystals that are not as dense and not as big as like the growable.

We’ll go floatin up to the top of the cloud, and then, the gropple has got one charge, like it’s stolen an electron, so now it’s negatively charged, and it’s like a lot of gropple particles becoming negatively charged. And then all these ice crystals are positively charged, because they’re missing an electron.

And they, so they go flying up to the top of the storm, and that’s what we call charge separation. And so what you get is you get like a region of, this is a, this is a simplification of it a little bit, but you get like a layer of negative charge here, a layer of positive charge here. And for the engineers in the crowd, you basically get something you can model as like a capacitor.

So you end up with a very strong electric field that forms in between those layers of opposite charge and the exact mechanism by which the electric field gets big enough to initiate lightning. is still a little bit it’s still a subject of research because it’s something that happens on so small of a scale that we can hardly measure it.

It’s really difficult. But you get some particles that move a little bit too fast in that electric field, and they will locally enhance it. To a point where it becomes so large that you get dielectric breakdown, is what it’s called. And so there’s a, the electric field is too hot, is too much, so there’s a spark, and the lightning will initiate in that region, and then the branches of it will spread into the other into those regions of charge, and The lightning carries the opposite charge from what it’s traveling through.

So you’ll get like negative lightning leaders going into a region of positive charge and they cancel each other out. It’s a really cool, complicated process that like, I’m from a meteorology background, so like I get the basic physics, but there are people who dedicate their entire careers to like the minutia of that.

Process.

Joel Saxum: So we’ve been seeing that we’ve read about this in a couple of papers that have been published. Now we’ve been seeing it in a lot of videos and storm chasing basically people sharing on dash cams and all kinds of stuff. We’ve seen this phenomenon more and more lately. And I think probably it’s once you see a white car, then all of a sudden you’re gonna buy a white car, you see a bunch of white cars on the road.

So now we’re really looking for it, so we’re seeing it everywhere. But we’ve also tracked the phenomenon in wind farms getting struck. So what it looks like in my mind, that is a, not a lightning engineer. I’m not Alan. I’m not Dr. Liz here. But what we’re seeing is as charge builds in the clouds is these large positive strikes around the cloud.

Say six, eight, 10 miles away, and then subsequent, as soon as that discharge happens. The turbines in a wind farm reaching up with upward leaders and then connecting to back to the cloud So almost like within a tenth of a second or even in five hundredths of a second big charge over here positive and a bunch Of smaller, that one might be plus a hundred kiliamp and then a bunch of like negative seven kiliamp charges Negative ten kilometers all reaching up within the from the turbines and connecting to the cloud.

How does that happen?

Dr. Elizabeth DiGangi: Upward lightning, what you’re describing, like these things that go up from the the turbine blades. Are you saying you see them like connect with the cloud and then have like return strokes? Yeah. So that kind of upward lightning has been documented to be usually preceding in, in a large discharge in the cloud.

So as much as you’re saying, like you see a positive strength come up miles away, there’s still a big in cloud component, any cloud to ground lightning that you see. starts in the cloud and there’s stuff going on in the cloud while that ground strike is happening. So that stuff going on in the cloud, now I just described how, these leaders will traverse charge regions to neutralize them.

What they’re not actually getting rid of the charge, what they’re doing is depositing new charge. It’s really weird. But so because of that you can get complicated like downstream effects to the electric field in the lower part of the cloud compared with the higher part where this big discharge is happening.

So now since this has, it can actually help enhance the electric field locally, further down. And then when that happens, you’ve got all this, you’ve also got all this like charge that’s been imposed on the ground surface. That’s the surface. You get all the, any electrons that can count, you’re like, rising up or pushing down depending on the charge in the cloud.

And so your surface is like ready to go. It just needs something. So that activity happens up in the cloud and locally enhances the electric field low in the cloud between the cloud and the ground enough that now there’s something there that can Initiate this upward leader and wind turbines in particular are interesting because they’re spinning usually quite fast, right during or maybe they’re turned off sometimes during the during big storms and whatever.

Joel Saxum: But yeah, if they’re not at a high RPM, it’s because the wind is going too strong and they’re curtailed or they’re they’re flapped negative or flat so that they’re not getting damaged because this is the time like you said earlier when there is these. lot of energy and a lot of wind and you have the wind shear and these things are blowing and blowing.

Dr. Elizabeth DiGangi: So if those, that wind turbines like spinning, if it’s moving, that point moving quickly through that air, you’ll actually get an enhancement of electric field right on the end of that point because it’s moving quickly. And so that then can initiate in the right, these conditions of all have primed it for this will initiate this upward leader.

And upward lightning is just, is really interesting because it’s very similar to downward lightning, but the beginning part, instead of it, you have a leader that goes up, connects with the cloud and whatever charges up there. But instead of having an actual like return stroke, like you would see in a cloud to ground strike, it just hangs out.

And there’s some evidence that it has continuing current. While it’s doing that so there’s like a constant continuous current flow up and down between the in this case the wind turbine and the cloud and then after that starts and then you might get we call it a subsequent return stroke then you would get like a normal cloud to ground activity it’s almost there’s an upward lightning that sets up this continuing current kind of connection between the wind turbine and the cloud and then there is after that it starts acting like regular downward lightning you get it.

Return strokes, return stroke. It’s very weird.

Joel Saxum: So what we’re seeing, what we see, we’re seeing in the field, Liz, is that those upward lightning strikes that are hanging out with that long duration current flowing through them. Those are the ones that are causing the bad damages in the field.

Those are the ones that are starting blades on fire and burning blade tips off and causing these larger damages. And they are at a loss sometimes, like why did this happen? And everybody’s looking for the 200 kiliamp strike. That’s what they’re like. It has to be one of those super bolts or something.

It’s no, that’s not what’s happening.

Dr. Elizabeth DiGangi: It’s actually that continuing current. It’s really interesting that you bring that up because I didn’t know that about like wind turbines, mostly like having damage from the upward lightning that has that continuing current. But, a big subject of research in the lightning community also right now is like, what kind of lightning initiates wildfires?

And we find that while the soil, like fuel dry, like how dry it is tends to be more important than the lightning itself. But it’s, we hypothesize that lightning with continuing current is more likely to initiate wildfires. And it’s for the same reason that it would do all this damage, which is that you have this electrical current flowing without interruption into this thing.

It’s gonna make it really hot and make it maybe explode. And re a regular ground stroke, just like. Hits, return stroke, hits, return stroke, hits, return stroke, but it’s like multiple different strike points. It’s not just one. So it’s, even if it hits the same thing multiple times, the lack of continuity is really critical for that.

Joel Saxum: But so that’s what’s happening in these wind turbines, right? So like you get that continuing current and normally, the down conductor in a wind turbine blade, they’re huge. They’re, I don’t know, six ought cable. I mean that they’re three quarter inches of a wide of cable, right? Yeah, they can handle it, no problem.

However, when you sit there and just cook on them with long duration, that’s when it gets hot. That’s when you can actually ignite the resin systems or the matrix, the, the balsam matrixes or whatever that’s inside that blade. And that’s when you can run into these massive catastrophic failures.

Allen Hall: I’ll throw in another piece to this, which we’re realizing is these damaging strikes, the one that caused fires and one that does all the expensive repairs on wind turbine blades. tend to be, at least look like, are upward strikes. And because there’s so many wind turbines in a small area, relatively small area, that there’s probably four, five, six, eight, ten of these wind turbines reaching up to the sky simultaneously, that what you get on some of these turbines is only continuing current.

They do not, they are not recorded on lightning location services. It’s amazing to see it.

Dr. Elizabeth DiGangi: Yeah. When you don’t have that return stroke, you don’t have like that. There’s no. There’s no major electric field change happening when you don’t have the return stroke. So yeah, that would explain why those aren’t always picked up.

Allen Hall: So when operators call Joel and me and say, Hey, it looks like we have lightning damage, but the Lightning Location Service doesn’t record anything. That’s why. It’s because, like Liz has described here, it has mostly to do with upward lightning and because those systems are not set up to pick that up, it’s almost impossible to pick them up.

That continuing current up by itself with a remote sensor like the lightning service is used.

Dr. Elizabeth DiGangi: Continuing current is very difficult to measure. There are a lot of researchers who have looked for ways to do it and there are a few ways to go about it. But. It usually requires some pretty sophisticated, like expensive equipment.

And so like the earth networks, what a lightning network that I work with at AEM it’s a global network, which is great. We can detect lightning all over the world in real time and we can classify it as cloud to ground or in cloud. And it’s great. It’s really fun to work with and, but the basic like concept that behind the detection that we do and which most mid to long range lightning detection systems do is that we’re actually picking up on radio waves that are emitted when there’s like a strong current, like a strong surge of current that’s like abrupt that changes the electric field where it is.

And it sends out these waves and now lightning emits all kinds of radiation, but the radio waves are the ones that can travel very far. So like your AM radio, your ham radio stuff, it’s the same kind of idea. And so that’s what we’re picking up on, but yeah, these upward strikes, if they’re not doing that, they’re not surging, they’re just flow.

They didn’t have current just smoothly flowing and they’re not really making like a localized electric field change. If the, if that upward strike doesn’t initiate an actual actual return stroke, like a, that would look like a ground one. It’s going to be very difficult if not impossible to detect with long range systems.

Allen Hall: Yeah. And I think in the Midwest, this is, goes back to the discussion about these huge storms. When you sit out and watch these thunderstorms happen, you watch a lightning strike. So they’re not simple lightning strikes. There’s not a bolt of lightning, boom, And then nothing happening in the cloud.

And then another one, boom it’s boom. And then flashes across the cloud. Simultaneously, the clouds trying to charge all these things up instantaneously. So the electrical activity is super complicated and the engineers in the world, like me, in order to understand it, try to break it down to really simple elements, but what the reality is, lighting is.

extra complicated. It’s not even really well understood, even if we can map it. And Liz, I think you have been around lightning mapping arrays. Those are the tools that detect what’s happening in the cloud. But if you don’t have that, like at a wind turbine site, you really don’t have a lot of tools there to know what kind of lightning has hit your turbine.

Dr. Elizabeth DiGangi: It’s a really difficult problem. The Earth Networks system in, if you have a lot of our sensors, you can make out, in like large flashes, you can make out like branch structure of all the things we detect in them, but in general, yeah, in those storms you’re talking about, like in supercells, there’s so much lightning happening so fast that you’re lucky to get locations of individual flashes.

In, uh, the big one that I studied in grad school was like, it got up to around the time when it was producing that five inch tail, it was over, it was over 400 flashes per minute.

Joel Saxum: Wow. But but we’re still, when we talk about that, when you talk about the LMA system and different sensing systems, of course, the, in my mind, the first and always thing that everybody’s using lightning detection for, no matter if you’re on a sports field or a wind turbine technician or whatever, it’s for safety, right?

It’s lightning in the area. Get the people to safety and, power down equipment if you have to, whatever, blah, blah, blah, blah, blah. But the other side of the things that we’re trying to get a little bit more advanced on is operations and maintenance, right? So when you talk about like the doing the crazy stuff with the Indian government for monitoring for space shuttles, right?

Now think about that’s an operations and maintenance problem. It’s just like a wind turbine because if that shuttle gets struck while it’s sitting on the pad, you just shot your launch in the foot, right? You’re shutting that down Until you can completely inspect the whole, I don’t know, everything.

Cause you’re not going to throw people on there and go ah, I hope it works. Now that’s been hit by lightning, send it up. You’re not going to do that.

Allen Hall: So let’s talk about the 2023 AEM earth networks, lightning report, which you had a hand in compiling because it’s an interactive report, you just Google AEM.

2023 lightning report and boom, you’ll go right to the website that has this really cool summary of what’s happening in the lightning world in the United States. But until you go through some of that data and it’s like I said, it is very interactive. You can select a lot of different things.

The lightning environment in the United States is really complicated. And there’s, there was some pieces in that data that I had not thought about before. You want to give us a quick summary of what’s all in there and why we should be looking at it?

Dr. Elizabeth DiGangi: Yeah. So the annual lightning report, that is something that I do.

I do all the number crunching and my some of my colleagues actually make it look good as on the virtual report. Yeah. Basically, you, we break it down where we look at lightning flash density. So like how many per square mile by state and county. And we do tracking what we call thunder hours, which is, you might’ve heard of the thunder day before, thunder hour, like same idea.

It’s did I hear thunder near this location, but instead of an entire day, it’s per hour. And we actually generate. Thunder hour data for the whole world that goes back to 2014 with our lightning, the Earth Network’s lightning data, which we just do a little bit of math and it’s okay, if there was lightning here, you could probably hear thunder out to about 10 miles away, 15 kilometers.

So mark that as a thunder hour. So in the, we include the thunder hours in the lightning report because it gives you context of where were there storms? Because I was just saying how this big supercell can make 400 flashes per minute, but that’s that’s one storm. One storm could hit that’s that strong, could hit in, Minnesota.

And then, wow, that looks like a huge anomaly in lightning density. If you compared it to the long term average. But if you said that’s just one storm, it doesn’t look like that big of a deal. So the thunder hours give you an idea of where it was the most stormy compared where there was the most lightning.

And those two things combined with we also have a maps of our how many dangerous thunderstorm alerts, AEM issues by state. These are DTAs, we call them, they’re, and it’s an automated storm tracking algorithm that tracks cells of lightning data, specifically, and once there is the total flash rate exceeds some threshold it’s deemed to be like, this is a dangerous storm, there’s a lot of lightning being produced in it, and we think it’s in, we’ve calculated that it’s moving in this direction, so we issue an alert.

It’s similar to severe severe thunderstorm warning from the National Weather Service, except that it’s, as I mentioned, it’s generated automatically and it’s just based on the lightning. So it’s really good for if you care about lightning safety. So those things combined can give you the full story of like, all right, where in the U.

S. saw lots and lots of lightning? Where in the U. S. saw lots more, lots and lots of storms and maybe more storms than the long term average? There was above average activity here, below here, average here. And then where were these storms deemed have a lot of lightning happening very fast?

And that’s where those DTAs were. So it lets you really get the big picture from multiple different directions.

Allen Hall: That’s impressive. And obviously if you’re a wind turbine operator and you have a lot of technicians running around, some of these farms have, 50 technicians out in the field.

Employee safety is so critical. The AEM earth network system that does provide alerts, gives you a heads up. Hey there’s lightning in the area. You better get out of there. Those are. Invaluable services that help the wind community. And it’s amazing to see those in action. You see the guys out in the field with them.

That’s pretty cool.

Dr. Elizabeth DiGangi: And AEM also has we have for people who, or, maybe when farm operators and owners who want a little more customized stuff. We also sell custom alerting systems. We’ve installed many of them at airports for different airlines who are worried about their ground crews.

Which will basically give you an alert if you have, if there’s lightning detected within whatever radius you want of your location. And then on top of that, if you want to get really into the details, we actually have a team of forecasters who work shift, who work, shift work round the clock 24 7.

We have forecasters on staff who will do like custom forecasts for clients of the company. So if you want some, if you want some like personalized made by a human weather forecast for your wind farm, like we’ve got that.

Joel Saxum: That might be huge for people listening that are operators, or, if you’re looking at the procurement side of things for blade work or something like that, like scheduling these people, because one of the things that the.

The wind farm budgets get soaked up by standby time, right? And you’re just paying lightning moves in or whatever. You’re paying people to be at on the site or at hotels. That’s a huge budget burn.

Dr. Elizabeth DiGangi: Yeah. And weather forecasting is a lot harder than a lot of people give credit for and weather forecasters are a lot better at their job than most people give them credit for.

It’s very difficult, but forecasters who have been around for a while and our team are all very experienced, like they know what they’re doing and they know what they’re doing better than. any individual forecast model does. It’s really I admire them so much for the work that they do.

Allen Hall: Yeah, I guess you get what you pay for in weather prediction, right?

This is why people reach out to AEM. And while we’re speaking of that how do you connect with AEM, especially if they want to talk lightning, how do they get ahold of you?

Dr. Elizabeth DiGangi: If you go to the website, aem.eco, There is like a, in the contact us, like there’s a form you can fill out and just, I’m curious, want to know about a thing.

We also have a pretty active LinkedIn page where our, the fine folks in our marketing department make sure to keep everyone who follows up on, what we’re up to. Cause the company does more, a lot more than just lightning. And we also do flood alert monitoring, wildfire, alerting, monitoring, stuff like that.

It’s really all encompassing from a lot of different types of hazards and we’re really like, as a company, we’re really dedicated, we are genuinely really dedicated to the safety side of it and to like, understanding these things more, that’s why they have research scientists on staff, and as a research scientist it’s a much, a There’s a much more genuine concern about these things here than I maybe thought there would be when I left academia to come into the private sector. It’s been really nice, honestly, to experience. It’s a really great place to work and a lot of very knowledgeable and skilled people in it.

Allen Hall: Liz, this has been great to have you on the podcast. I’ve learned a lot. I know Joel has learned a ton about lightning and storms and it’s fun. I know it’s fun to talk about lightning. So we want to have you back. So we’re going to invite you back, especially as the storm season progresses. But thank you so much for being on the podcast.

Dr. Elizabeth DiGangi: I’d love to come back. Thank you for having me.

https://weatherguardwind.com/aem-lightning-expert-weather-risks-wind-farms/