Emergency managers in western Iowa are preparing for the Missouri River to crest above flood stage this week from high amounts of rain in the forecast, bringing another round of possible flooding to the area.
The National Weather Service forecasts 1 to 3 inches of rain between now and Wednesday morning for southwest Iowa to eastern Nebraska. Some localized areas could see at least 5 inches. The rainfall is also predicted to trigger a rise in the Missouri River. Models predict the Missouri River will rise a little less than 5 feet and crest at 33.2 feet at the Omaha, Neb. gauge – more than 1 foot above moderate flood stage – on Thursday, Oct. 3.
“The runoff from this heavy rain is one of the things that’s kind of the most difficult to predict – just exactly how much will run off and end up causing rises in the rivers,” said Bryon Miller, a meteorologist with the National Weather Service in Omaha/Valley, Neb.
Miller said increased flood potential is there, but “what makes things somewhat uncertain is the timing of the rainfall and the rainfall amounts.”
It’s also unclear how current breaches in levees and other protective structures will affect localized flooding. A third round of flooding in mid-September breached three protective structures in northwest Pottawattamie County, including a levee. Michael Bertacini, an emergency management specialist with the county, said emergency personnel still have not been able to reach the areas to put fresh dirt down and fill the breaches.
“We haven’t seen the water levels this high since those breaches to see how it’s going to affect the area,” Bertacini said. “It’s not that it’s not concerning, it’s just that we’ll have to wait and see what happens to get an accurate representation of what it will do differently than with intact levees.”
In a joint news release, emergency managers from Pottawattamie, Harrison and Mills counties urged people to be prepared for more possible flooding, calling the current forecast “one plausible scenario for the upcoming rainfall event.”
“What we do know is that over the next 72 hours we are going to see a heavy precipitation event of 4 to 5 inches of rain somewhere in the region; what we don’t know for certain is where it will fall,” said Pottawattamie County Director of Emergency Management Doug Reed in the statement.
The impacts could mirror what the county saw in March, though the river could crest about a foot lower this time, Bertacini said.
“All the county roads in the northwest part of the county on the west side of I-29 were basically underwater,” Bertacini said. “I-680 and I-29 also went under. It forces the water table to rise in Council Bluffs.”
Bertacini said people who live in Council Bluffs could see basement flooding if the storm sewers are not able to keep up with the heavy rainfall.
Around 40 homes are in the area of concern in the northwestern part of the county, but most of those residents are already out of their homes.
The rising Missouri River, which is expected to crest at 31.3 feet on Friday, Oct. 4 at the Plattsmouth, Neb. gauge, less than 1 foot under moderate flood stage, “compounds the problem from the third round of flooding” for Mills County, said Mills County Public Information Officer Sheri Bowen.
The floodwaters from mid-to-late September that came through a breach and affected Mills County have not receded, Bowen said. Mills and Pottawattamie counties are also expecting some problems from the West Nishnabotna River.
“If you live near a body of running water, you need to be alert,” Bowen said.
A flash flood watch is also in effect from Monday evening to Wednesday morning for smaller streams and ditches in the area.