If you woke up in panic with gray eyes Monday morning and wondered why someone set off fireworks directly over your bedroom, you are not alone.
Shortly before 06.00, when lightning struck World Trade Centerstruck thunderbolts on the eardrums of sleeping New Yorkers.
What happened? According to several meteorologists who spoke to Gothamist, the ear-wearing wake-up call can be traced to a phenomenon known as thermal inversion.
A reversal of normal temperature behavior, an inversion occurs when a layer of hot air traps cold air directly beneath it – essentially transforming our street scene into nature’s Motorhead show.
As John Homenuk, a meteorologist at New York Metro Weather, explains: “This inversion can act as a lid in the atmosphere, so when lightning strikes, the sound waves get trapped beneath it and they echo back to us on the ground, causing them to sounds much louder than usual. “
The inversion also allows the sound waves to travel longer distances – possibly explaining why the ear-splitting thunder stretched from Brooklyn over New Jersey.
Although inversion in itself is not terribly uncommon, a number of factors, including its location and the slow thunderstorm, combine to make the experience memorable for many.
“It probably happens a couple of times a year, but when it happens over a larger metropolitan area like New York City, it seems a little more unusual,” said Dominick Ramunni, a meteorologist at the National Weather Service.
This is not the first time that a temperature inversion has cultivated a shared sensory experience. Back in 2005, in the early days of what would later become a year-long city-wide mystery, an inversion layer was suspected of helping to capture the smell of maple syrup within the nostrils of New Yorkers and New Jerseyers.