In Bixby, a Tulsa suburb of 24,000 on the river, where the National Guard is filling sandbags, officials texted an alert Tuesday morning: “As soon as residents believe the situation warrants, they are encouraged to evacuate voluntarily.” In Tulsa, the state’s second-largest city, officials continued to monitor the levees, but said the dam and the levees in Tulsa County were so far working as they should.

“We are planning for and preparing for the flood of record, and we think everybody along the Arkansas River corridor ought to be doing the same,” the mayor of Tulsa, G.T. Bynum, told reporters on Tuesday afternoon. “While it’s high risk, there is not an emergency behind the levees right now. It’s a high-risk situation when you’re talking about infrastructure that’s being tested in such a strong way.”

Braggs is usually a slow-paced town, home to 259, in the hilly country in Muskogee County nearly 100 miles east of Tulsa. It’s a place of farmland and giant catfish. Low-flying fireflies flicker in the night sky amid the music of the frogs. In the pitch-black countryside Monday night, a young man on a dirt bike pulled up to the edge of the flooding, unzipped his backpack and started fishing. Something that sounded like a gunshot rang out: Locals figured someone had shot a snake, which have been rampant in the floodwaters.

But making do with so little access to the outside world has been difficult. There were not a lot of amenities in town to begin with. There is one gas station (it was out of gas but reopened Tuesday), a couple of restaurants, a convenience store and Donna’s Malt Shop — but no grocery stores.