(CNN) -- Louisiana officials are investigating whether an underground salt cavern may be responsible for a large sinkhole that has swallowed 100-foot-tall cypress trees and prompted evacuations in a southern Louisiana bayou.
The state's Department of Natural Resources ordered Texas Brine Company, which mines the cavern, to drill a well into the cavern to see whether it caused the dark gray slurry-filled hole nearby.
Measurements taken Monday showed the sinkhole measures 324 feet in diameter and is 50 feet deep, but in one corner it goes down 422 feet, said John Boudreaux, director of the Office of Homeland Security in Assumption Parish, about 30 miles south of Baton Rouge.
Assumption Parish police said Thursday the sinkhole has since grown another 10 to 20 feet.
The sinkhole appeared August 3, more than two months after local residents started noticing bubbles in the water. The bubbles grew in number and frequency, and in some spots they made the bayou look like a boiling crawfish pot, said Dennis Landry, who owns guest cabins about half a mile from the hole.
Assumption Parish police ordered the evacuation of all residents in the area, though Landry said it's not a forced evacuation so he and his wife have decided to stay.
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