Every morning, Mexico City wakes up to the sight of a mountain that refuses to behave. Popocatépetl—”Smoking Mountain” in Náhuatl—has been puffing away like a chain-smoker since December 1994, when it decided to end a 70-year nap with a bang that sent ash 25 kilometers into the sky.
Here’s the thing about Popo: it’s one of North America’s most active volcanoes, sitting just 70 kilometers southeast of one of the world’s largest metropolitan areas. Twenty-five million people live close enough to see its ash plumes on a clear day. That’s more humans than live in all of Australia, casually coexisting with a geological time bomb.
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The Aztecs knew something was up. They built Tenochtitlán with one eye always on the mountain, weaving Popo into their mythology as a warrior transformed into stone. Smart move, considering the volcano has had at least 15 major eruptions since 1519.
Turns out the mountain’s been playing this game for roughly 730,000 years.
In 2000, officials evacuated 41,000 people when Popo burped out its largest eruption in 1,200 years. The ash cloud reached 8 kilometers high, blanketing towns in gray powder and shutting down Mexico City’s airport. People returned weeks later to find their homes looking like they’d been dusted by the world’s most aggressive housekeeper. The volcano caused an estimated $300 million in agricultural damage that year alone—crops don’t appreciate being buried under volcanic debris, apparently.
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Wait—maybe the fascinating part isn’t the eruptions themselves but what’s happening underneath. Popo sits atop the Trans-Mexican Volcanic Belt, where the Cocos Plate slides beneath the North American Plate at about 6 centimeters per year. That subduction zone is basically Earth’s pressure cooker, melting rock into magma that desperately wants out.
The volcano’s current phase started with a distinctive pattern: small explosions every few weeks, each one ejecting ash, steam, and volcanic gases. Scientists at CENAPRED, Mexico’s National Center for Disaster Prevention, monitor Popo with 12 seismic stations, thermal cameras, and GPS sensors that measure the mountain’s literal breathing—how it inflates and deflates as magma moves beneath the surface.
Between 2012 and 2023, Popo produced more than 500 exhalations and explosions. Some barely noticable, others sending incandescent material cascading down its slopes like demonic waterfalls.
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The villages clinging to Popo’s flanks have a complicated relationship with their volatile neighbor. Farmers in places like Santiago Xalitzintla, just 12 kilometers from the crater, cultivate corn and beans in volcanic soil so fertile it almost makes the risk worthwhile. Almost. When Popo rumbles, they check the alert level—Verde, Amarillo, Rojo—and make calculations that would terrify urban planners.
In 2019, the volcano entered an especially energetic phase, with explosions occurring every few hours. The ash column reached 3 kilometers on May 8th, forcing flight cancellations and school closures across central Mexico. Puebla, a city of 3 million sitting 40 kilometers away, got covered in fine gray powder that infiltrated everything—cars, lungs, water systems, that burrito you were trying to eat.
Yet people stay.
They stay because their families have farmed these slopes for generations, because the soil produces maize sweeter than anywhere else, because moving means abandoning not just homes but identities. Mexican authorities maintain a 12-kilometer exclusion zone, but enforcement is… flexible. Monks still tend a monastery at 4,000 meters elevation, close enough to hear the mountain’s underground growling.
The next big one could happen tomorrow or in 200 years. Volcanologists can’t say for certain, which is either reassuring or terrifying depending on your tolerance for geological ambiguity. What they do know: Popo isn’t finished. Not by a long shot.
