My obsession with the roving mud puddle of Imperial County started several years ago, when my then-boyfriend sent me a YouTube video. Titled “Giant Moving Mud Puddle Tries to Take Out a TRAIN,” the clip from science influencer Physics Girl showed a brown, bubbling puddle some 50 feet from Highway 111, where the road runs along the Salton Sea’s eastern shore. In 2018, the muck traveled at least 60 feet over the course of several months, with some reports that it then matched that distance in one day. Nothing seemed able to stop its forward march, which terrorized California’s transportation authorities.
The Salton Sea’s eastern shore is home to hundreds of mud pots, though only this one—known as the “Niland Geyser,” “moving mud spring,” and “Mundo”— moves. Scientists can’t figure out why: Some think that a series of earthquakes made the bedrock more permeable and allowed the mud to seep through. But there’s no conclusive link. The region’s unique geology certainly plays a role: a highly faulted area with thick sediment that drains from the Grand Canyon through the Colorado River. A number of forces—tectonic activity, the accumulation of gases, the heat of young magma—conspire to force this sediment upward, resulting in puddles that spit and gargle like a witch’s brew.
The puddle dwelled, static, for more than 60 years in a farmer’s field until 2016 (though some officials dispute this timeline). Seemingly out of nowhere, the muck started moving southwest at a quick clip, at least as far as puddles go, digging a crater of slurry sediment and water 75 feet wide and 25 feet deep. By May 2018, the mud puddle was about 80 feet from the Union Pacific Railroad tracks, a stretch that is essential for the train’s entire Western operation. One month later, the Imperial County board of directors declared the area an emergency zone. Railroad officials contracted a geotechnical firm to build a sheet pile wall 75 feet underground to try to contain the puddle.
In October, the mud puddle slipped below the wall and reemerged even closer to the main train line, forcing Union Pacific to divert trains to temporary tracks they’d recently constructed in case of puddle emergency. “[The railroad company] came up with different ideas. None of them worked,” says Shawn Rizzutto, the division chief of maintenance for the California Department of Transportation’s 11th District, which covers San Diego and Imperial County. “You can’t stop Mother Nature. She’s got a mind of her own, and she’s going to do what she wants.” By August 2019, the problem was thrust upon the state’s transportation department. Caltrans shut down Highway 111 for a weekend as it built a road diversion, forcing travelers to drive an hour and a half out of their way, around the western shore of Salton Sea, to avoid the sludge.
Even the authorities desperately trying to stop the puddle can’t help but marvel at this geologic oddity. When he saw the mud puddle for the first time, Rizzutto was awestruck. He’d
worked for Caltrans for more than 20 years, maintaining roads and preparing cities for winter storms and rain, and he’d never seen anything like this. “How cool is this,” he remembers thinking. “We have the only moving mud pot in the world, and I get to work on it.” The puddle hasn’t moved since 2019 or so, Rizzutto tells me, but his crew goes out to check on it once a week, just to make sure.
Kevin Key, a real estate photographer who lives in an RV in Bombay Beach, is
convinced that the mud is still migrating, and headed again for the train tracks. Key is fascinated by the geologic mystery of the puddle and visits every month or two. He delights in its refusal to heed to authorities. “Generally, nature’s ultimately gonna win,” he says.
Only time will tell if the puddle will move again. For now, companies in the Imperial Valley have begun tapping into the same geothermal heat that warms the mud puddle—and are planning to extract lithium from that same resource below the Salton Sea. That lithium, in turn, could help the world transition away from fossil fuels. In the case of climate change, man’s interventions have had devastating consequences. But, as the mud puddle has shown, nature rules over man.•
Meg Bernhard is a journalist and essayist in Las Vegas. Her work has appeared in the New York Times Magazine, the Virginia Quarterly Review, the New Yorker, Harper’s, and other publications. Her book, Wine, published in 2023 as part of Bloomsbury’s Object Lessons series, is a meditation on wine and power.
