Lightning in the Northern Territory's Top End has entranced humans for thousands of years, inspiring creation stories, terrifying locals, and attracting meteorologists and storm chasers from all over the globe.
This is what's going on behind the clouds.
A flicker followed by a gurgling rumble is the first sign the show is about to start.
During Darwin's wet season, it's an almost daily occurrence, but that doesn't stop the city's residents from emerging onto balconies to catch a glimpse at the performance.
From an 18th-floor vantage point, you can see the monstrous purple mass hovering out to sea.
Beneath it, a column of haze suggests heavy rain somewhere many kilometres from where you stand completely dry.
The temperature drops several degrees, a welcome relief from the sticky humidity.
For a millisecond, veins of light crackle across the horizon.
Then the thunder, so loud it seems like a train is roaring across an old metal bridge above your head.
Darwin — Australia's most remote capital city, closer to Jakarta than Canberra — was once thought to be the lightning capital of the world, in a time when the phenomenon was only counted if it was seen or heard.
It's now number 381 on the global list of lightning hotspots, far behind Lake Maracaibo in Venezuela — which according to data from the International Space Station, experiences more lightning than anywhere else in the world with an average of 389 flashes each day.
The below map, published by NASA's Earth Observatory, shows the regions with the highest concentration of lightning. The tiny white spot at the top of South America represents Lake Maracaibo, while the bright blotch in Africa's east is Lake Kivu in the Democratic Republic of Congo, second on the list with an average of 368 flashes a day.
But like so many other things in life, sometimes it's about quality over quantity.
The Top End attracts storm chasers and meteorologists from all over the world, desperate to be there when a big bolt cracks open the sky.
They come for the incredible frequency of thunderstorms; during the wet season — from November to April — they emerge seemingly out of nowhere almost every afternoon.
Just one of these storms can produce thousands of bolts, each one many kilometres long, hotter than the surface of the sun and harbouring an electrical current of up to 30,000 amps.
And many locals and visitors agree: there's no better show on earth.
Chasing a front-row seat
There are few people more familiar with Top End thunderstorms than Mike O'Neill.
For the past two decades, the veteran storm chaser has been packing up his camera and hitting the road whenever there's a whiff of a storm within driving distance of his Palmerston home.
"You always say you're after the perfect shot. Well, I've got the perfect shot — but then you see another one," he says.
"There have been times where I've been burnt out, a storm's been in the area and my wife will go 'there's a storm out there', and I'll say 'ah, I don't care'.
"But it doesn't take long, two days later [I'll be out there]. It's like being on crack or something, I don't know.
In a year, Weatherzone estimates Darwin experiences 54 lightning pulses per square kilometre — making it the most lightning-prone capital city in Australia.
The actual lightning capital of Australia falls about 360 kilometres south-west of the city, roughly above the Nganmarriyanga community near Wadeye, with around 200 lightning pulses per square kilometre each year.
O'Neill's interest in thunderstorms began in 2002, when he was gifted a coffee table book by famed Australian landscape photographer Peter Jarver.
"It was his lightning shots that were the thing that sort of tweaked me," he says. "So I bought a little Sony point-and-shoot and was in the backyard trying to get photos, and it wasn't happening — I had no idea."
But recently, the chase has been about more than the perfect shot. Alongside a collaborator in the United States, O'Neill is currently researching "bolts from the blue" — lightning strokes that exit the side of a cloud and can hit the ground many kilometres away from the storm itself.
Earlier this year, the World Meteorological Organisation declared a 768-kilometre lightning flash in the United States the world record holder for distance travelled. The bolt covered a horizontal distance longer than the space between Melbourne and Adelaide.
"These clean air strokes, always happen first, nine times out of ten," O'Neill says. "I just wanted to understand why it's doing what it's doing."
One afternoon during the build-up, the period of high temperatures and unbearable humidity that precedes the monsoon, O'Neill offers to take us out on a chase.
The goal is to see some of these bolts for ourselves, but he warns that the movement of tropical storms is notoriously difficult to predict.
A short drive out of Darwin, near a suburb called Humpty Doo, he pulls over onto the side of a long, rural road. In front of us is a vast field speckled with communications towers. Above, the sky is turning an ominous grey and the wind is picking up.
Getting the perfect shot often means a lot of waiting around — and a lot of failed attempts — but O'Neill has a secret weapon in his kit.
Attached to his camera, sitting atop a tripod, is a sensor that picks up infrared light. Before a lightning bolt is visible to the human eye, the sensor is able to detect what's coming and automatically trigger the camera's shutter.
About 10 minutes in, O'Neill jumps back. "Woah, that's too close for me," he says. While our attention was focused on the field in front, a bolt has come down somewhere behind where we are standing.
It's a bolt from the blue.
This type of lighting is particularly dangerous, he says, because people standing under clear skies typically aren't looking out for it. "It's blue sky, a storm over there, then bang."
O'Neill decides the safest place, for now, is inside his car. In the event of a strike, a vehicle acts as a sort of protective shell — providing a crucial layer of conductive material between bodies and the supercharged bolt of electricity.
This caution is the result of plenty of "close calls" and one particularly terrifying incident. O'Neill tells the story of another bolt from the blue, which came down while he was out in the dark, early hours of the morning.
"It just went completely iridescent blue, and there was some ungodly roar that I'd never heard before, and it flew me to the ground," he says.
He waited for "what seemed like minutes" before mustering the courage to make the dash to his car. The photo taken at that moment almost looks like daylight. "I think what happened was the stroke had hit the ... powerlines above my car," he says.
"I don't want to be that close ever again."
It's estimated between five and 10 people are killed by lightning in Australia each year, and about 10 times that are injured.
Today, O'Neill's not taking that chance.
The anatomy of a lightning storm
Deep in Kakadu National Park, about three hour's drive from Darwin, there's an ancient art gallery. The rock paintings depict the creation stories of the original inhabitants of the park, Bininj and Mungguy people, and some are believed to be up to 20,000 years old.
Among the illustrations is a figure surrounded by a ring of electricity and axes protruding from the head, knees and elbows.
This is Namarrgon — the Lightning Spirit.
Aboriginal people from Kakadu believe Namarrgon uses his axes to create thunder and lightning as he moves through the landscape. These stories have been passed down through generations, with Namarrgon's arrival traditionally announcing the beginning of the monsoon.
"When we see these big storms coming, when we see the bright lights, that's when he's using his power," Simon Badarim told ABC in 2012.
"We know the story from the elders, don't you ever run when you see bright lights from the lightning, keep walking, keep walking."
Lightning is a powerful electrical discharge in the atmosphere (including within and between clouds) or from the atmosphere to the earth (known as ground strikes, cloud-to-ground, or CGs).
When this giant flash goes off, the sound it makes is thunder. You can tell roughly how close a storm is by the type of thunder you hear; a loud whip-cracking sound means a bolt has come down somewhere close, while rolling grumbles suggest it's further away.
As evidenced by Namarrgon, the Top End has been a hotspot for this phenomenon for thousands of years.
Joel Pippard, a meteorologist with Weatherzone, says this is because the region has an abundance of the three elements needed for lightning to occur.
The first ingredient, he says, is moisture — which is in high supply during the wet season.
The second is instability in the atmosphere, which occurs when warm air from the surface of the earth rises up and collides with the cooler air above.
The final element is "lift", or a trigger that pushes that warm air upwards to a point where it becomes unstable.
This could be a cold front that forces any warm air in its path upwards or mountain ranges that force the air to climb.
"Something special about the tropics, which isn't really true for southern Australia, is that there is so much moisture and instability that the lift doesn't have to be nearly as strong as it does in other parts of Australia," Pippard says.
"Something as weak as a sea breeze can actually create enough of a little bit of push to grab that air to a level where it will start to rise by itself."
Unlike other tropical regions, the Top End also has geography on its side. During the build-up, Pippard explains, strong south-easterly winds blow across northern Australia from the desert.
"So we're getting really hot air accumulating in that area, but we also have a humid sea breeze that comes in every afternoon ... so it's the area with the highest heat and the highest moisture," he says, "that extra instability and extra moisture provide extra energy once the thunderstorm gets going."
This explains not only why lightning storms are so frequent during the wet season, but also why when they hit, they're so powerful.
There's also a relatively simple explanation for why the storms seem to appear "like clockwork" in the afternoons: it takes time for the sun to warm up the ground enough to trigger instability.
Changing landscapes
But not all of Darwin — or the Top End for that matter — is created equal when it comes to where lightning strikes.
O'Neill remembers a time in the 80s and 90s when storms would hit the city so predictably at 4pm that locals called them "knock-off storms".
But in recent decades, things have changed. He says the main hotspots are now all within a sort of "rural belt", about 40 kilometres outside of the city.
In the city, the loss of vegetation has meant less moisture — and storms don't like dry air.
When the budding storm hits these unfavourable conditions, O'Neill says, it simply turns and pops up further afield.
"That's why we rarely chase in the city anymore," he says.
"You've got to do your homework to go after them."
The homework starts the day before, scouring forecast radars for indicators of instability and winds. The next day, he checks the radars again and the weather balloon which goes up at midnight. In the hours leading up to a chase, he's constantly monitoring.
"It's a bit like Photoshop, you have to get all the info, then lay it out in layers, then read it, then put it back together and see what it looks like as one complete picture," he says.
"It's definitely getting harder."
Some believe high concentrations of minerals in the ground around Darwin help attract lightning strikes, but Pippard says while it can be a factor in some locations, it's probably not as important as people think.
What does play a role in the number of strikes each year, however, are weather drivers like La Niña and El Niño.
During a La Niña cycle, waters around northern Australia are warmer, which means more moisture in the air. This leads to more thunderstorms, more lightning and even a higher chance of tropical cyclones. When it comes to El Niño, these conditions are reversed.
With a La Niña cycle currently underway, Darwin is in the midst of its second rainiest wet season on record. According to Weatherzone, the city has almost reached its entire wet season rain average despite being not even halfway through the season.
Storms have also been coming thick and fast. "With that monsoon trough that's currently there, we've seen lots and lots of thunderstorms, basically every day for the last three weeks or so," Pippard says.
But a particularly heavy monsoon is bad news for storm chasers; the lightning is still there, but it's shielded from view by curtains of rain.
We get a first-hand lesson on this when the rain moves in during our chase. After the close call, O'Neill decides we should try and outrun the deluge further up the road.
It's there, in a small parking lot accompanying a lively wetland, that a large motorhome inches into view. The number plate reads "AUS SKY".
Inside are Clyve and Jane Herbert, who — according to O'Neill — have "been chasing since the dinosaurs disappeared".
The couple split their time between the United States' midwest and life on the road in Australia, driven by the will of storms. As evidence of their dedication, Jane explains that Clyve has been struck by lightning multiple times.
That's why she stays in the car when it kicks off, she jokes, so someone can drive him to the hospital.
And the couple keep coming back to Darwin for one reason: it has the best lightning.
"The moisture here is just off the charts," Clyve says, before pointing to a large cloud on the horizon. "Have you heard of Hector?" he asks.
He's talking about Hector the Convector — a huge thunderstorm so regular and distinctive that it's earned itself a name. Located above a mountain range on the Tiwi Islands, off Darwin's coast, Hector reliably shows up at 3pm every day during the wet season — and has done so since at least WWII, when pilots used it as a navigational tool.
According to Pippard, it's the most regular thunderstorm in the world — and by virtue of that consistency, also the most studied, attracting meteorologists from all over the globe.
"There can be a huge pillar that can be easily seen from the ground in Darwin," he says, noting it's capable of reaching up to 20 kilometres in height.
"That's a special thunderstorm that Australia is home to."
Credits
Words and production: Maani Truu
Photography: Mike O'Neill and Michael Franchi
