Devices that measure water levels along the Missouri River show the river has finally dropped below flood stage between Sioux City and where the river meets the Mississippi River near St. Louis.
Sites farther downstream have higher chances of staying above flood stage for longer because more water comes in from nearby smaller rivers. The amount of water released from Gavins Point Dam in South Dakota was higher than normal, at 80,000 cubic feet per second from September through November, adding even more water to the river.
That is why the gauge at Nebraska City, Neb., close to southwest Iowa’s Fremont County lingered above flood stage for 270 days. It dropped below flood stage on Sunday. The gauge near Waverly, Mo., 200 miles northwest of St. Louis, dropped below flood stage early Tuesday morning. Other gauges, including Sioux City and Decatur, Neb., have been below flood stage for a while.
The Nebraska City gauge read above flood stage for 164 days in 2011, according to National Weather Service Omaha/Valley, Neb. Senior Service Hydrologist David Pearson. It remained above flood stage for 100 more days this year, and it’s not typical for the Missouri River to be so high for this long, Pearson said.
“It shows just how extreme and how much water had to move through, not just in Nebraska and Iowa, but also in the Dakotas,” Pearson said. “And a lot of the water that went through came from the Dakotas.”
In a post on social media, Fremont County Emergency Management said though the Missouri River is expected to continue to fall, it “does not mean that we are out of the woods yet.”
“We still have water out that is trapped as it cannot get back into the river at this time until the river drops lower,” Fremont County Emergency Management said. “Additionally, we still have roads closed due to flood damage and in some places the roads [are] no longer there and we still have water over some roads in the western section of the county.”
Conditions in the Missouri River Basin "are favorable for another flood next year," Pearson said. It is still unclear how severe that flood could be.
"But with the wet soils, and a lot of the rivers are higher than normal, those two things alone contribute to an increased flood threat," Pearson said. " And if we get a lot of precipitation — snow and rain, it will make it potentially that much more worse."