Floodwaters swamped more than half a million acres of forest and farmland in the lower Mississippi Delta more than six months ago, gulping up highways and homes, livestock and tractors. This week, for the first time since, the river gauge at Vicksburg on the western border fell below flood stage.

“This is biblical proportion,” Paul Hartfield, an endangered species biologist with the United States Fish and Wildlife Service, said of the floods. “Nothing like this has ever been seen.”

Climate change is increasingly turning the extraordinary into the ordinary. Extreme floods and snowfall, at times moving to extreme heat and droughts, are forcing cities and farming communities across the country to grapple with the threat to their homes and livelihoods.

In the Yazoo Basin, a section of the delta where farming is the linchpin of the economy, people are still struggling to cope with a flood that seems forgotten by nearly everyone outside the disaster zone.