Spring flooding again threatens both sides of Iowa, National Weather Service forecasters reported Thursday in the first of three predictions leading up to the season.
The early outlook shows a 95 percent probability of major flooding again this year along the Mississippi River on the state’s eastern border.
After last year’s record floods, the weather service in the Quad Cities added a third spring-outlook discussion to its typical twice-a-year-outlook schedule.
The first of such reports was released Thursday, indicating current conditions are “similar” to those that were present heading into last spring.
“We do have potential for another significant year of flooding, especially on the Mississippi River,” said Jessica Brooks, service hydrologist for the service in the Quad Cities.
She cited several factors in assessing the likelihood the Mississippi will again climb above its major flood stage of 18 feet: already-high river levels; substantial snow pack to the north, which has particularly high water content; and the depth of the frost line, which causes precipitation to run off the ground rather than absorb.
“The main snow pack is to the north,” Brooks said. “There’s a lot of water sitting up there.”
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Sarah Jones, chief of emergency management for the Army Corps of Engineers Rock Island District, said the agency already has taken steps to help the Quad Cities — Davenport in particular — to prepare for another round of major flooding.
In addition to monitoring river levels and looking “more than before” at ways to help in the next flood fight, she said, the Corps conducted training exercises this week with Davenport Public Works. The goal is to achieve the maximum benefit out of temporary sand barriers, which the city uses to protect the downtown from floods.
When a section of the temporary levee failed last April 30, lower downtown was inundated. As a result, the Corps evaluated the city’s use of the sand-filled baskets and made specific suggestions on how to better erect and maintain them.
Cedar Rapids used similar sand barriers in 2016 to fend off a high Cedar River, but with far better success.
The Corps has assembled “flood teams,” Jones said, to help monitor levees, offer technical training and spot “distress areas” throughout the 78,000-square-mile jurisdiction of the Corps’ Rock Island office.
The region includes 129 levee systems.
Ideally, the mild temperatures that are expected in coming weeks will help reduce the flood risk, Brooks said.
If temperatures remain above freezing, conditions would improve because the snow pack would thaw slowly. Plus, the frozen ground would run off slowly, and the ground could absorb more precipitation.
“Comparing today to a year ago, there is more snow on the ground now,” Brooks said. “But February storms to the north piled more on last year. The outlook for storms are not as daunting” this year.
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The Missouri River along the state’s western border faces an elevated risk of spring flooding.
The forecast heightened concerns in areas of Iowa, Nebraska, Kansas and Missouri with levees that still have extensive damage from massive flooding last year.
“We are very concerned at this point,” said Jud Kneuvean, who oversees emergency operations at the Army Corps’ Kansas City office. The weather service said Nebraska, Iowa, Kansas and Missouri have an above-average flood risk this spring.
Even in places where the Corps has patched holes in levees that were damaged in last year’s flooding, the level of protection may be lower than it was because initial repairs haven’t all been done to the full regular height of the levees.
Officials say levee repairs will likely take two years to complete.
The status of levees varies greatly. In Iowa and Nebraska, many of the major levees have been patched, though some breaches remain.
Most of the breaches around western Iowa’s Hamburg have been patched, but some repairs probably won’t be done until spring, said Fremont County Emergency Manager Mike Crecelius.
“It’s not a good outlook no matter how you look at it,” he said.
The Associated Press contributed.