This weekend, while most of us celebrated the March thaw, the mayor of Fargo set out in search of April floods.

Every melting pile of slush and snirt sends runoff trickling up the north-flowing Red River, creeping up its banks, closer and closer to Fargo and everyone else along the Dakota-Minnesota border.

The river will rise this spring, almost everyone agrees on that.

The question is, how high?

Just to be on the safe side, Mayor Tim Mahoney put Fargo on emergency footing last week. Volunteers will fill the first of 1 million sandbags on Tuesday, stacking them on pallets, ready for delivery to neighborhoods around the city.

That might sound like a lot of sandbags, but a decade ago, it took 100,000 volunteers and 6 million sandbags to save Fargo.

Mahoney listened to forecasters laying early odds on the 2019 season, and whether it could be as bad as 2009, when sandbags piled up on the flood walls and snow fell on the sandbags and the Red River of the North rose higher than anyone in Fargo had ever seen.

He listened, then made plans to head out on Highway 46 to see for himself.

That’s what mayors of Fargo do this time of year.

This weekend’s road trip down side roads, past reservoirs and around flooded fields will retrace the steps of the mayor who taught the mayor — the late folk hero, flood fighter and flood whisperer Dennis Walaker.

Walaker, who died in 2014 shortly after winning his third term, spent decades trying to keep the Red River outside the city limits, first as a city engineer, then as head of public works and finally as mayor. Every spring, he trekked south to see what the spring melt had in store for his flood-prone city, just across the river from Moorhead, Minn.

On some of those trips, he would deputize Mahoney, his deputy mayor, to do a little legwork for him.

“He’d say, ‘Tim, go out and walk into this ditch and tell me when you feel water on your feet,’ ” Mahoney said.

While Walaker observed from the roadway, comparing what he was seeing with flood years past, his deputy mayor — a trained vascular surgeon — waded off into the muddy fields.

“I’d say, ‘Denny, is there a better way than sending me in the ditch?’ ” he said. “ ‘Like maybe a pole we could stick down there?’ And he’d say ‘Oh no. It’s a lot of feel. You’ve just got to feel what the ground is like.’ ”

Walaker, a man with a keen eye, sharp mind and booming laugh, died of cancer at age 73, leaving his city to fight the Red without him. When Mahoney followed him into office, his phone started ringing after the first thaw. Farmers along Walaker’s old route wanted to know when the new mayor was coming down for a cup of coffee and a talk about the weather.

“I’m still learning,” said Mahoney, who planned to take the trek with some of Walaker’s longtime friends and fellow flood whisperers. “It was often just knowing what the ground was doing: How much water is being absorbed? Is the frost line gone? There were all sort of hunches he would get from that.”

Mahoney will deliver his observations in coming days to a city that has seen more than its share of bad forecasts.

Fargo has flooded 53 times since 1903, according to U.S. Army Corps of Engineers, which is working on a massive flood control project that will throw miles of flood walls and channels around the city to sweep future floodwater up and around the city and its homes and businesses.

The past few years have been dry, though, and when Mahoney made the rounds of the schools last week, looking for student volunteers to help out with the sandbagging, one puzzled teacher asked if there was a YouTube video the children could watch to learn how it’s done.

Filling and stacking sandbags, Mahoney said, “if you’ve ever done that, it’s an immense amount of labor, an immense amount of work.”

The trick to sandbagging is not to overfill the bags. If you fill them about three-quarters full, Mahoney said, they’ll stack better and they’ll be light enough for anyone to pick up and throw.

When the river rises, schools and businesses close in Fargo. Everyone who can grabs a shovel or a bag and gets to work. Volunteers stream across the border from Moorhead, too, which sits higher on the riverbank and is a few feet safer from the Red.

“We just love it when we get into the full [flood] season, because we have people from all over who want to help out,” Mahoney said. “They see a neighbor’s having trouble and they want to come and give a hand.”