How a sinkhole caused a whirlpool and formed Louisiana’s deepest lake

While Louisiana’s largest lake, the Toledo Bend Reservoir, spans 1,200 miles of shoreline, the state’s deepest lake only spans 1,125 acres.

Lake Peigneur is the deepest lake in Louisiana, with a depth measuring approximately 200 feet.

Lake Peigneur is a brackish lake, meaning it contains saltwater but has less salinity than seawater, located in New Iberia Parish in South Louisiana.

How did Lake Peigneur become the deepest lake in Louisiana?

Lake Peigneur was not always considered the deepest lake in Louisiana, as it was only a 10-foot-deep freshwater lake 40 years ago.

On Nov. 20, 1980, an oil rig crew was attempting to free a 14-inch drill bit when they heard popping noises and the rig began to tilt. Shortly after the crew abandoned the rig and headed for shore, the crew watched the 150-foot oil rig disappear into the 10-foot-deep lake.

Soon, a whirlpool formed in place of the oil rig. The whirlpool grew rapidly until it was able to suck up nearby boats, barges, trees, a house and half an island.

At the same location of the oil drilling site, there was also a salt mine, and when the whirlpool formed after the oil rig collapsed, the mine began to fill with water. As the whirlpool grew, water was able to enter the mine at such a force that it caused a geyser to spew out of the mine’s opening for hours until the lake was drained.

After the lake was emptied, the Delcambre Canal began to flow backward, marking the only time in history that the Gulf of Mexico flowed into the continental U.S. This backflow continued until the entire mine and lake were filled with water, except now the lake was filled with saltwater, according to an article published on Louisiana Tech Digital Commons.

Can you swim in Lake Peigneur?

Before the oil rig and salt mine accident, Lake Peigneur was a popular spot for fishing and recreational activities. However, since the lake is almost entirely surrounded by private property, visitors will have to enter the nearby Rip Van Winkle Gardens in order to get a closer look, according to Atlas Obscura.

While there are no reports indicating the lake is unsafe, the lake is not exactly developed for public access. However, there are things to do around Lake Peigneur, like visiting Rip Van Winkle Gardens on Jefferson Island, or visiting Avery Island to tour the Tabasco Factory.

Presley Bo Tyler is a reporter for the Louisiana Deep South Connect Team for USA Today. Find her on X @PresleyTyler02 and email at PTyler@Gannett.com