By: Elaina Zachos, National Geographic
Frank Neumann got quite a shock around 1 a.m. on Thursday when he heard a sinkhole open up at his retirement community in central Florida. A few hours later, around 3 a.m., police knocked on Neumann’s door and told him he had to leave.
“I heard some noise,” Neumann tells WCJB. “I thought it was thunder. Evidently that was the ground crashing in on the sinkhole.”
Five other sinkholes have opened up in the area. In addition to Neumann’s home, one other house has been condemned and two have been evacuated.
But how do sinkholes form? Why does Florida get so many of them? And what’s with the nearby lake draining like a bathtub? Those questions explained below:
CAVING IN
Sinkholes are depressions that gradually form in the ground when water erodes an underlying layer of rock or soil. There are two types, and the type in this video above occurs when water has dissolved the rock underneath soil to create a gaping cavity sheathed with only a thin layer of earth. Without support from rock, the top soil layer collapses.
Sinkholes are common in areas where groundwater can naturally dissolve the rocks below the land surface. Soluble rocks like salt beds and domes, gypsum, limestone, and other carbonate rocks are high-risk materials.
Florida is no stranger to sinkholes, and the Sunshine State has been plagued by them before. Resorts and other homes have been swallowed in the past. About 20 percent of the U.S. is susceptible to sinkholes, and the landscapes of Texas, Alabama, Missouri, Kentucky, Tennessee, and Pennsylvania are also attractive terrain for these natural phenomena.
After the sinkholes swallowed land in the neighborhood, a nearby lake quickly began to drain at a “fairly rapid pace,” says Paul Bloom of the Marion County Sheriff’s Office. (Watch: “Mesmerizing Drone Footage Shows ‘Whirlpool’ Draining This Lake”)
CBS News reported the lake was manmade, and workers at a nearby golf course were trying to drain it to remedy the situation.
