Over the next few days, water spewing through a Mississippi River floodgate will crawl through the swamps of Louisiana's Cajun country, chasing people and animals to higher ground while leaving much of the land under 10 to 20 feet (3 to 6 meters) of brown muck.
The floodgate was opened for the first time in nearly four decades, shooting out like a waterfall. Fish jumped or were hurled through the white froth and what was dry land soon turned into a raging channel.
The water will flow 20 miles (30 kilometers) south into the Atchafalaya Basin, and from there it will roll on to Morgan City, an oil-and-seafood hub and a community of 12,000.
In the nearby community of Stephensville, rows of sandbags were piled up outside nearly every home.
Merleen Acosta, 58, waited in line for three hours to get her sandbags filled by prisoners, then returned later in the day for more bags.
Floodwaters inundated Acosta's home when the Morganza spillway was opened in 1973, driving her out for several months. The thought of losing her home again was so stressful she was getting sick.
"I was throwing up at work," she said.
The opening of the spillway diverted water from Baton Rouge and New Orleans, and the numerous oil refineries and chemical plants along the lower reaches of the Mississippi. Shifting the water away from the cities eased the strain on levees and blunts the potential for flooding in New Orleans that could have been much worse than Hurricane Katrina.
The Morganza spillway is part of a system of locks and levees built after the great flood of 1927, which killed hundreds and left many more without homes. When the Morganza opened, it was the first time three flood-control systems have been unlocked at the same time along the Mississippi River, a sign of just how historic the current flooding has been.
Earlier this month, the corps intentionally blew holes into a levee in Missouri to employ a similar cities-first strategy, and it also opened a spillway northwest of New Orleans about a week ago.
Snowmelt and heavy rain swelled the Mississippi, and the river has peaked at levels not seen in 70 years.
About 25,000 people and 11,000 structures could be affected by the oncoming water, and some people living in the threatened stretch of countryside — an area known for fish camps and a drawling French dialect — have already fled. .
The crest of the Mississippi is still more than a week away from the Morganza spillway, and when it arrives, officials expect it to linger. The bulge has broken river-level records that had held since the 1920s in some places.
This is the second spillway to be opened in Louisiana. The corps used cranes to remove some of the Bonnet Carre's wooden barriers, sending water into the massive Lake Ponchatrain and eventually the Gulf of Mexico.
By Sunday, all 350 bays at the 7,000-foot (2,100-meter) Bonnet Carre structure were to be open. The Morganza, a 4,000-foot (1,200-meter) long structure built in 1954, was expecting to only open up about a quarter of its 125 gates.
The spillways could be opened for weeks, or perhaps less time, if the river flow starts to subside.
In Vicksburg, Mississippi, where five neighborhoods were under water, a steady stream of onlookers posed for pictures on a river bluff overlooking a bridge that connects Louisiana and Mississippi. Some people posed for pictures next to a Civil War cannon while others carried Confederate battle flags being given away by a war re-enactor.
Larry and Paulla Dalrymple spent part of the day with a video camera, filming the river roll past a casino and swirl around the giant bridge pilings.
"Wow. It's really running,"' Paulla said. "It's amazing what the water can do — what it's doing to people's lives."