Despairing resident Pierre Watermeyer told CNN, simply: "It's over with, it's over with."
"It's worse than we thought," resident Kelli Trimm told the news network as the town scrambled to gather belongings and flee.
"It's going to take everything, everything we've got. It's scary. It's going to take out our whole community," she said.
If the Morganza Spillway were not opened in time, the Corps warned earlier this week, flooding reaching as high as 25 feet (7.6 meters) could be expected to soak New Orleans.
The worst floods to hit the central United States in more than 70 years have already swallowed up thousands of homes, farms and roads in Illinois, Missouri, Kentucky, Tennessee and Mississippi.
Heavy rains last month filled rivers and creeks already swollen from the melting of a thick winter snow pack, and which are now backing up because the Mississippi is so full.
The American Red Cross said back-to-back disasters over the last two months has prompted it to launch 23 separate relief operations backed by over 7,700 relief workers in 18 states, from North Dakota to the southern coast, and along the eastern seaboard.