The federal government said Wednesday that 20 to 30 more levees may overflow the Mississippi River from Burlington, Iowa down to St. Louis.
Twenty levees have already overflowed this week, the Army Corps of Engineers said. The other levees could overflow if sandbagging efforts fail to raise the levees' levels.
The levees in danger protect rural, industrial and agricultural areas - not heavily populated towns. The levees protecting large towns are not as at risk of overflowing, officials said.
Record-breaking storms and flooding across six states this month are still forcing thousands of people to evacuate. Since June 6, there have been 24 deaths and 148 injuries because of the storms and flooding, according to federal briefing documents obtained by The Associated Press.
In the flooded regions, some food processing plants are expected to be shut down, and officials expect maritime transportation to be closed for at least a week.
As of Wednesday morning, the federal government has provided about 2.5 million liters of water; 146 generators, more than 213,000 meals, more than 10 million sandbags and 1,200 rolls of plastic sheeting, according to FEMA and Army Corps tallies.