A third of the United States is at risk of flooding this spring, including 23 states and 128 million Americans. That’s according to the spring flood outlook released by the National Weather Service on Thursday.

The forecast for significant spring flooding comes a year after one of the worst seasons on record in 2019. But this year, the flooding isn’t expected to be quite as severe.

The Northern Plains and Upper Midwest are forecast to be most at risk, but flooding concerns stretch along the entire Mississippi River. As spring rains increase and snowmelt to the north surges into river basins, a number of rivers and streams may overflow their banks and inundate nearby land.

Particularly vulnerable this season is the Deep South, where many cities have already had close to 30 inches of rain since the start of the year and soils are saturated. The National Weather Service is forecasting moderate flooding over larger areas of Mississippi, Alabama and Georgia.

A rough season, but not as bad as 2019

Scientists at the National Oceanic and Atmospheric Administration emphasized that, while an above-average spring flood season is anticipated for many this year, flooding is unlikely to be as widespread or severe as it was a year ago.

“Last year we experienced widespread historic flooding across much of the U.S.,” Mary Erickson, deputy director of the National Weather Service, said in a call with reporters Thursday. “Nearly 165 million people were impacted. And flooding continues to be a factor for many Americans this spring.”

She said that major flooding was most likely to be confined to the Northern Tier states, with the greatest risk of flooding associated with the Mississippi River basin, the Missouri River basin and the Red River of the North. Last year, moderate to major flooding occurred in a much larger swath of the country.

Bob Holmes of the United States Geological Survey said that last year, about 107 stations saw record flooding and that this calendar year is off to a fast start.

“We’ve already had 28 of our stream gauges report record peaks,” he said.

Stormy pattern eyes Upper Midwest and Northern Tier

A number of areas are heading into spring flood season well ahead on rainfall (and snowfall), leading to saturated soils that will have a tougher time handling the imminent downpours of springtime. That could have an impact, especially for farmers.

“Overall, we don’t expect flooding to be as bad as 2019,” said Brad Rippe of the U.S. Agriculture Department. “Up in the northern Corn Belt, Red River Valley in the north, they’re still trying to finish the corn harvest. Wet soil could be an issue.”

“If you put that in context with the forecast over the next few weeks and look ahead over the next couple weeks, it looks like a very active southwest to northeast storm track,” Rippe said. “[That leads] to a wet pattern over the Upper Midwest. That pattern, coupled with the forecast for the spring, means we will be facing some potential planting delays.”

Many farmers in the Corn Belt endured devastating floods in March 2019. Hard hit was Nebraska, where the Platte River spilled into Omaha. The local Weather Service office staffers were forced to abandon their posts and evacuate to higher ground. They later resumed duty at an office approximately 160 miles away in Hastings, Neb.

This year, moderate to major flooding may still target the Dakotas and western Minnesota, but Nebraska will probably experience mainly minor flooding.

Major flooding is also anticipated along the James River in South Dakota, as well as the Upper Little Sioux. About 1.2 million people could be at risk.

Other tributaries of the Missouri River are expected to see moderate flooding.

Saturated soils a problem in Deep South, Southeast

Saturated soil is also a problem in the Southeast, which has dealt with a seemingly endless battering of heavy rain and flooding this spring. Water rescues and school closures were needed in Alabama in mid-February, with some communities approaching 30 inches of rain to start the year. In many Southeast cities, the 2019 to 2020 meteorological winter was among the top five wettest on record.

The report indicates that moderate flooding is likely at times in Mississippi, Alabama and Georgia — which are already waterlogged in some areas.

“Moderate flooding means some inundation of roads,” said Ed Clark, director of the National Water Center in Tuscaloosa, Ala. Major flooding can begin to widely affect structures.

Typical flooding along Mississippi River

Along the Mississippi River, seasonal minor to moderate flooding is anticipated, with a few pockets of major flooding likely along the Iowa and Illinois border.

But even where flooding doesn’t crest in the major category, some locales may see long-duration flooding, which can have an impact in other ways.

“In 2019, the Mississippi River at Cape Girardeau was above flood stage for 144 consecutive days,” said Erickson, of the NWS. “Many flood events can span weeks or even months.”

Clark said that flooding along the Mississippi could be exacerbated by anomalously warm temperatures, which have induced snowmelt across much of the northern Mississippi River Basin.

Regardless of how the spring season pans out, Erickson emphasized that any flooding should be taken seriously.

“Flooding can cause more damage than any other weather-related event,” she said. “It’s an underrated killer … causing more than 100 deaths a year, half in vehicles.”