Southern Minnesota motorists know the stretch of road well.

Right where the the Jolly Green Giant billboard stands grinning on a hillside, U.S. Hwy. 169 dips from the prairie down into the wooded lowlands below Le Sueur.

Unlike vast stretches of the farm-rich region, the highway here bellies up to the undulating blue ribbon of the Minnesota River, which, during wet months, can picturesquely rise nearly to motorists’ eye-level.

It’s both natural marvel and foe. Tornadoes whip through the valley. Ice can cake narrow roadways. And then there’s the rain, which can swell this seemingly tamed waterway into a monster roaming up the hillsides.

Over the years, the Minnesota River (and nearby roadways) have flooded often. The years are like notches on a doorway: 1965, 1993, 2019.

As often, stretches of U.S. Highway 169 north from Mankato and St. Peter downstream through Le Sueur and near Henderson have been closed.

But earlier this century, state officials poured millions into a renovation of Hwy. 169, including lifting up a steel bridge hundred of feet, spanning south central Minnesota’s mightiest waterway outside Le Sueur.

The hope was the roadway could withstand even a once-in-a-century flood. Vital traffic ferrying emergency vehicles, grain trucks, or even visitors trekking up or back from the Twin Cities might not need to veer off onto alternative routes or cancel trips altogether.

But then came the 2024 floods.

As of Wednesday afternoon, the highway between Le Sueur and St. Peter remains shuttered for the second day in a row.

In an Air National Guard hangar in St. Paul on Tuesday, after jumping off a helicopter following an aerial tour that brought Gov. Tim Walz and Sen. Amy Klobuchar hovering over the imperiled Rapidan Dam southwest of Mankato, and the dramatic watery deluge of homes in Waterville, Walz noted that, after providing safety for residents, those charged with rebuilding structures need to deal with a new normal about extreme, climactic events.

“If I recall right, the engineers built [that bridge over the Minnesota River] for a 500-year flood,” Walz said. “That was 14 years ago. So, the 500-year flood came in 14 years.”

Actually, state officials said Wednesday, the low steel bridge that opened in 2008 was built to withstand a 100-year-flood.

Still, it’s far from the only roadway inundated. By Tuesday, the bridge on Highway 93 into Le Sueur was underwater.

“That bridge deck has never been fully under water in its history,” said Joe Roby, Le Sueur’s city administrator. “That is one of the only east-west crossing points over the river between Mankato and Chaska.”

Flooding is a geography lesson about a region’s interconnected river and transportation system — and a sleepless exercise for workers. By Wednesday, Minnesota Department of Transportation crews had opened one northbound lane on Hwy. 169, as crews pumped water leaching onto the highway.

Roby continued to watch with amazement from his hometown. Just a few months ago, with the state deep in drought, he said his 6-year-old daughter could throw a stone across the Minnesota River.

At another press conference on Wednesday, Lt. Gov. Peggy Flanagan acknowledged the traffic blockade as a public safety necessity.

“I also know that having 169 being closed can be an annoyance,” Flanagan said. “But it’s really, really important for people to follow those detours, to stay safe and to avoid driving through any water.”

“[U.S.] 169 is a huge corridor of commerce,” Roby said. “There’s a tremendous amount of people and goods and services who rely on getting to and from the metro, from Iowa or the Mankato area, or Worthington or South Dakota. It’s really extraordinary.”

And a changing climate means better preparation against these forces of nature, in an ever-extreme climate.

During Tuesday’s press event, Sen. Amy Klobuchar spoke about flood mitigation efforts in Duluth and Austin that followed extreme water damage for homes and businesses.

“We do know we save communities in future flood[s] when we do something now preventative,” Klobuchar said.

Klobuchar even noted her own husband and daughter were stymied in their attempts to visit the in-laws in Mankato.

But like other Minnesotans at this moment, accustomed to this passageway, there’ll need to patiently wait-out this mid-summer hiatus before the river slowly returns to its old banks.

“When you see all the water,” Klobuchar said, “you understand what’s going on.”