How much higher will the Waccamaw River rise?

The Waccamaw River is expected to flood, again, in the next few days thanks to expected rainfall from Hurricane Irma.

The question federal forecasters are trying to figure out: how much will it flood?

Now that Irma is positioned to pass north along the Georgia and Alabama border, Pfaff said Friday the Waccamaw has a 50-percent chance of exceeding minor flood stage of 11 feet by next week.

That’s if Horry County and the surrounding areas only get three inches of rain.

When predictions still called for Irma to tear a path through the middle of the state, forecasters were concerned about several scenarios showing the Waccamaw reaching moderate flood stage at 12 feet, said Steven Pfaff, warning coordination meteorologist for the National Weather Service.

“There still is uncertainty,” Pfaff said. “Even though the cone has shifted away from our area we still have some tropical storm force probabilities.”

“Given the uncertainty and given the track errors, we’re totally not out of the realm of this. So I don’t want people to let their guard down,” Pfaff said.

The river gauge at Conway shows the water has been steadily declining since reaching flood stage last week, and registered at 10.8 feet on Friday.

“Right now, we feel like the rainfall is manageable across most of our forecast area,” Pfaff said.

Weather officials are more concerned about the five inches of rain expected in the Santee River counties of Williamsburg and Georgetown, Pfaff said.

Additionally, Pfaff reported there are 40 to 50-percent chance of water exceeding minor flood stages on the Black Creek at Quinby and Pee Dee at Pee Dee by early next week.

The Little Pee Dee at Galivants Ferry stands a 50-percent chance of cresting just below minor flood stage, and the Lumber River at Lumberton could reach action stage by Wednesday.

“These are very preliminary and the actual rises would be highly dependent on specifically when, how much, and where the rainfall occurs Sunday night into Monday,” Pfaff said.

“Ultimately, it is highly dependent on Irma's eventual track.”

This story was originally published September 8, 2017 at 4:33 PM with the headline "How much higher will the Waccamaw River rise?."