As Harmon Maher walked along the Keystone Trail in central Omaha one morning in February, he noticed something unusual: the creek beside the path, usually a gray-green shade, flowed bright orange.
The water carried heavy sediment, likely from upstream construction, the retired geology professor assumed. Maher didn’t dwell on it until hours later, when his son informed him about an incident quickly becoming the talk of the town.
A section of Pacific Street, about the size of a sand volleyball court, had collapsed into the ground, swallowing a silver Ram pickup truck and a maroon Jeep Cherokee. The sediment Maher had seen in the creek had washed out from beneath the road, forming a large void that caused the vehicles to fall in.
“I was sorry I wasn’t still teaching,” Maher said. “I would’ve probably spent (time) in class saying, ‘Look, here’s the relevance. Here’s geology in action. Here’s a sinkhole.’”
Videos capturing the exact moment the road gave way quickly gained millions of views worldwide. However, most sinkholes in Omaha don’t attract that level of attention.
Over the past five years, city work crews have reported more than 2,100 “cave-ins,” ranging from minor pavement dips to large gaps like the Pacific Street sinkhole. Although most cases remain small, Omaha experiences more cave-ins than several other Midwestern cities, according to a Flatwater Free Press analysis.
Geologists attribute the city’s vulnerability to its soil composition. Much of Omaha sits on loess (pronounced “luss”), a fine-grained sediment that water can easily carry away, leaving empty spaces underground.
“It’s great for growing corn, but terrible for building roads,” said City Engineer Austin Rowser.
This happens because the state is one of the few without significant karst topography. Dissolvable bedrock makes regions like the Missouri Ozarks and Florida’s “Sinkhole Alley” more prone to large sinkholes, said Matt Joeckel, Nebraska’s state geologist and a professor at the University of Nebraska-Lincoln.
In contrast, Omaha’s sinkholes tend to be shallower and usually result from interactions between human-made infrastructure and the fine sediment covering eastern Nebraska, geologists explained.
“We’re not going to have a situation in which a giant sinkhole suddenly appears … and continues to grow and eat up a neighborhood,” Joeckel said.
When a pipe breaks or a sewer leaks, water can wash away loess or underground fill dirt. Omaha’s hilly terrain further supports this movement, said Maher, who taught at the University of Nebraska at Omaha for four decades.
Rowser suggested that the Pacific Street sinkhole may have started months earlier as a small leak in a Metropolitan Utilities District water main. The water likely entered the storm sewer, gradually forming a void that went unnoticed. Over time, enough soil shifted into the sewer to create a large cavity, which eventually collapsed under the weight of two vehicles on Feb. 24.
However, MUD disputes the city’s explanation, arguing that a damaged storm sewer caused the sinkhole and that the water main broke only after the collapse.
As both sides debate the sequence of events, the city and MUD have filed claims against each other to cover repair costs.
Since 2021, Omaha has averaged more than 400 cave-ins each year, based on Public Works data analyzed by Flatwater.
Many of these appear as minor dips in roads or sidewalks. According to Rowser, the city installed barricades for around 40% of cases, indicating potential surface hazards.
Omaha records significantly more sinkholes during warmer months, as frozen soil resists erosion, Rowser noted. This sets them apart from potholes, which usually develop when moisture enters pavement cracks during freeze-thaw cycles in late winter and early spring.
UNO geology professor Ashlee Dere said she isn’t surprised by the number of cave-ins in Omaha, given its soil conditions, modified landscape and aging infrastructure.
“It’s surprising in that it doesn’t cause more problems,” Dere said.
Over the years, Omaha has experienced several notable sinkholes. In 2014, a collapse on St. Mary’s Avenue swallowed a car and injured its driver. Last year, another downtown sinkhole pulled half of a garbage truck into 16th Street and remains under repair following a yearlong dispute between the city and a property owner.
Still, Rowser reassured drivers that the chances of a vehicle falling into a sinkhole remain extremely low.
The two drivers involved in the Pacific Street collapse escaped without injuries.
Although the risk of harm remains minimal, engineers must remember that they are building on soil prone to rapid erosion, Joeckel emphasized.
Beneath the Surface
Officials must inspect every cave-in to prevent sinkholes from forming, and in Omaha, Public Works crews handle that responsibility.
When the city receives a report, an employee examines the site to identify the underlying cause, Rowser said.
Workers typically begin by injecting colored dye into a hole or crack in the pavement.
If the dye appears in downstream sewer water, it indicates that water and sediment are leaking into the system. Crews then send a camera through the pipes to trace the flow and locate the entry point before making repairs.
If the dye doesn’t appear in the sewer, the issue may stem from an animal burrow or a decaying tree root. In such cases, workers fill the void using a specialized concrete.
Reports of cave-ins have declined in recent years, dropping from more than 500 in 2021 to about 340 last year. However, geologists warn that aging underground infrastructure could increase Omaha’s risk of sinkholes.
Recently, the city has explored new methods to detect underground issues, Rowser said. Fiber optic cables, for example, could help identify leaks in water lines and alert officials early.
Joeckel added that certain geological surveys could reveal where water collects and highlight potential problem areas.
“It would be great if you could see what was going on below the surface before something happened,” Joeckel said.
Rowser admitted he isn’t sure what signs might have warned of the Pacific Street sinkhole beforehand. City workers conducted a dye test late last year while examining minor surface settlement, but it didn’t indicate a sewer breach.
After the collapse, construction crews moved quickly to repair damaged pipes and fill the missing section of roadway.
The street reopened just nine days after closure. By then, the sinkhole had gained global attention, with coverage from major outlets including The New York Times, USA Today and Fox News, along with international media from Belgium to Vietnam.
According to Rowser, the incident’s viral popularity largely stemmed from a University of Nebraska at Omaha security camera that captured the dramatic collapse.
“If a picture’s worth a thousand words, I don’t know what a video is worth,” Rowser said. “It’s got to be a lot more.”
Maher believes the widespread fascination also reflects human psychology.
“I suspect it has to do with the psychology of how we are intrigued by the unexpected,” Maher said. “It’s unexpected that the ground that is so solid and firm beneath your feet just gives way.”
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