"What we're worried about now is all that snow melt in North and South Dakota and Minnesota," Keith said.
AccuWeather meteorologist Alan Reppert said it may stay cold long enough up north to make for a gradual melt, giving the rivers time to thin out. Of greater concern, he said, is the Red River in North Dakota, which could see significant flooding in the coming weeks.
Along the Mississippi, a handful of river towns are most affected by the high waters — places like Clarksville, Mo., and Grafton that have chosen against flood walls or levees.
By Sunday, sandbagging had all but stopped in Clarksville, evidence of the confidence that the makeshift levee hurriedly erected to protect downtown would hold.
The river was at 34.7 feet Sunday, nearly 10 feet above the 25-foot flood stage — a somewhat arbitrary term the National Weather Service defines as the point when "water surface level begins to create a hazard to lives, property or commerce" — and expected to rise another foot before cresting Monday.
"We believe we'll have a successful conclusion," said Jo Anne Smiley, longtime mayor of the 442-resident hamlet.
Richard Cottrell, a 64-year-old antique shop owner, was hopeful, but nervous. After two days of sandbagging, Cottrell thought he could rest Saturday night, but the constant beeping of heavy equipment outside and flood worries kept him up.
"I had a rough night last night. I had an anxiety attack," he admitted.
Many towns on smaller rivers in other states were dealing with floodwaters, too.
In Indiana, high water was topping levees in the Terre Haute area. Vigo County Emergency Management Agency Deputy Director J.D. Kesler said late Sunday afternoon the barriers haven't failed yet but that some evacuations will be necessary if levees fail in the western Indiana county.
In Grand Rapids, Mich., Mayor George Heartwell declared a state of emergency as the flooding Grand River poured into the basements of several hotels and other downtown buildings.
Illinois Gov. Pat Quinn declared at least 44 counties disaster areas from flooding. The Fox River in northern Illinois reached record levels, and several record crests were possible along the Illinois River.
Salter reported from St. Louis.