According to Weatherzone, the city has almost reached its entire wet season rain average despite being not even halfway through the season. With a La Niña cycle currently underway, Darwin is in the midst of its second rainiest wet season on record. When it comes to El Niño, these conditions are reversed.ĭarwin is currently experiencing almost record rainfall. This leads to more thunderstorms, more lightning and even a higher chance of tropical cyclones.
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What does play a role in the number of strikes each year, however, are weather drivers like La Niña and El Niño.ĭuring a La Niña cycle, waters around northern Australia are warmer, which means more moisture in the air. 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. "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. In the hours leading up to a chase, he's constantly monitoring. The next day, he checks the radars again and the weather balloon which goes up at midnight. The homework starts the day before, scouring forecast radars for indicators of instability and winds. In the city, the loss of vegetation has meant less moisture - and storms don't like dry air. He says the main hotspots are now all within a sort of "rural belt", about 40 kilometres outside of the city. 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".īut in recent decades, things have changed. Changing landscapesīut not all of Darwin - or the Top End for that matter - is created equal when it comes to where lightning strikes. 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. This explains not only why lightning storms are so frequent during the wet season, but also why when they hit, they're so powerful. 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." "So we're getting really hot air accumulating in that area, but we also have a humid sea breeze that comes in every afternoon. During the build-up, Pippard explains, strong south-easterly winds blow across northern Australia from the desert. Unlike other tropical regions, the Top End also has geography on its side. "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." "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. 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. 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. "I just wanted to understand why it's doing what it's doing." "These clean air strokes, always happen first, nine times out of ten," O'Neill says. The bolt covered a horizontal distance longer than the space between Melbourne and Adelaide. 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.Įarlier this year, the World Meteorological Organisation declared a 768-kilometre lightning flash in the United States the world record holder for distance travelled. "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."īut recently, the chase has been about more than the perfect shot. "It was his lightning shots that were the thing that sort of tweaked me," he says. O'Neill's interest in thunderstorms began in 2002, when he was gifted a coffee table book by famed Australian landscape photographer Peter Jarver.
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