How and why sinkholes form in the Ozarks

SPRINGFIELD, Mo. — The heavy rainfall the Ozarks has experienced over the last few weeks has led to some sinkholes opening in roadways across the area.

One sinkhole opened up on Richwood Road in Ozark between Highway 14 and Fremont Road. Ozarksfirst drove by the sinkhole Wednesday and found it was repaired. With more rain on the way, geologists said more of these issues could pop up.

“A lot of [sinkholes], we feel that these things have been forming for years,” Greene County Geologist Matt Forir said. “So every rainy season, it just kind of works a little bit more dirt out of the way. At some point, you have basically you’ve got this void that forms.”

Forir said water is the catalyst for sinkholes. He said the Ozarks are rich in limestone and soluble rock, two materials he said are soft and weather away easily.

“You have those two [rocks] and it forms Karst,” Forir said, “It has the ability to do some, some serious collapses and erodes away things.”

Forir said there are many places sinkholes can take shape. There is a map on the Greene County Assessor’s website showing thousands of sinkholes in Greene County.

“You look at the map, you see these linear clusters of sinkholes,” Forir said. “Those are on the upthrown sides of faults. So geology does dictate where the sinkhole is going to be.”

Forir said the sinkholes are not always like the one on Richwood Road in Ozark or the one on James River Freeway last summer. He said out of the 8,000 sinkholes in Greene County, several are in people’s backyards.

“It’s starting to warm up, people are starting to get outside,” Forir said. “They’re starting to do yard work, cut their grass, and that’s when they first notice these things. The ground gives way because now you’ve got the added weight on top of that and that’s how you find it.”

Forir said there are ways to prevent a sinkhole from forming near your home.

“Get those downspouts far away, pipe them away, get a reputable landscaper to trenched these things and pipe them away,” Forir said. “Dump them into a storm sewer, dump off the backs of the property.”

A stretch of Farm Road 193 over Pierson Creek in Greene County has been closed for almost a month when a hole opened up in the roadway after a period of heavy rain. Forir said water did cause the hole to open, but he’s not sure it’s technically a sinkhole.

The county did not mention a timetable for when the closed portion of Farm Road 193 will open back up. It said it is waiting for the water levels in the creek to drop so it can make the necessary repairs.

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