Wooded mountains, painted badlands, shining canyons – the Chihuahuan Desert is known for its wondrous landscapes. But there are further wonders concealed beneath this rugged terrain. Spanning the Texas-New Mexico border, the Guadalupe Mountains contain more than a hundred caves. They’re widely regarded as among the most beautiful in the world.
The most famous, of course, is Carlsbad Cavern, in New Mexico – half a million people visit the national park here each year. Now, cave scientist Riannon Colton is working to unlock one of the cavern’s mysteries: its “speleometeorology.” Because it turns out that big caves, like big mountains, create their own weather.
“I love the Guads,” Colton said. “They are really decorated. They're extensively beautiful. And some of these caves are really large.”
Colton discovered caving a decade ago. She’s since caved in 26 U.S. states and eight foreign countries. In 2025, she spent 125 days underground, entering uncharted subterranean realms.
Now, as a University of Arkansas PhD student, Colton is focused on two hazardous gases within Carlsbad Cavern. One – carbon dioxide – comes from visitors; humans exhale CO2. The other is radon, a naturally occurring radioactive gas produced by uranium in the cave’s limestone walls.
Workplace-safety regulations designate acceptable exposures to these gases, and the national park has long monitored their average quarterly levels. But for a more nuanced picture, Colton deployed six weather stations, which record gas levels, barometric pressure, wind speeds and more.
Most were placed in accessible locations – including the famous “Big Room” that visitors tour. But Colton placed one in a high chamber known as Spirit World. She regularly ascended a 220-foot rope to download data, and to switch out the station’s 55-pound battery.
“In the Big Room that's that rope hanging from the ceiling,” Colton said, “and I would have to climb with the battery once a month or once every two months to replace it.”
It’s a task fit only for a serious caver. Colton often had help from friends in the closeknit caving community.
Carlsbad Cavern is 30 miles long and almost 800 feet deep, and the atmosphere within that vast labyrinth is complex. Colton said there are two meteorological phenomena that shape airflow in the cave.
The first is a barometric mechanism. Because the cave’s volume is so immense, and its points of access to the surface so small, air can surge in or out of the cavern as barometric pressure on the surface changes.
The second phenomenon is called “circulating convective airflow.” When the surface atmosphere is cooler than the cave’s, cold, dense air sinks into the cavern’s depths.
“It's kind of creeping along the floor until eventually it's warming up,” Colton said, “becoming less dense, and it'll rise to the ceiling, and it'll flow out along the ceiling to the same entrance. It creates a convective cell.”
Colton found these mechanisms operate seasonally. The convective cell dominates during cooler months, beginning in October. But in April, the cell “shuts off,” and the barometric mechanism determines the cave atmosphere.
Colton found that the circulating convective cell keeps gas levels low in winter, and that concentrations rise in summer. There’s no risk to visitors. But Colton’s findings could be important for park interpreters, who spend hours in the bowels of the cavern.
“Because of the high-resolution monitoring of both concentrations of gases,” Colton said, “you can figure out how long your cave employees can spend in the cave interacting with visitors while following OSHA requirements.”
Colton is expanding her research to other caves. For cavers and scientists, she said, there’s still much to discover in these shadowy spaces.
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