Although the torrential rain from Florence may be coming to an end in the Carolinas, the slow-motion disaster of river flooding will continue to wreak havoc across the region for days – or potentially weeks.

It may take up to two weeks for all of the runoff from the storm, which has killed at least 32 people, to drain slowly downstream from the mountains to the coast, forecasters warned. As of midday Monday, 19 river gauges in the Carolinas were at "major" flood stage, the National Weather Service said, and record crests could be challenged or shattered in some communities.

Nearly 20 rivers in the Carolinas were expected to crest in major flood stage this week, the Weather Channel said.

"Just because much of the rainfall has stopped does not mean the danger has ended," the National Weather Service in Wilmington, North Carolina, said Monday.

Officials warned that this could be the worst flooding in the state’s history. "Flooding has become catastrophic in some areas, and access to some communities will only be possible by boat into later this week," AccuWeather meteorologist Mike Doll said. "This is truly a life-threatening situation."

Rivers such as the Cape Fear, Lumber, Waccamaw and Pee Dee are most at risk. In Lumberton, North Carolina, the Lumber River crested at a record high of 22.18 feet Monday morning.

“It’s hard going through it all over again,” Lumberton resident Bruce Mullis said, recalling Hurricane Matthew's rampage in 2016. “It’s only been two years. It’s honestly traumatizing.”

In Fayetteville, the Cape Fear River is forecast to crest at 61.8 feet Tuesday, which is more than 25 feet above flood stage and 7 feet below the all-time record. Thousands of people were ordered to evacuate in that city as the rivers rise.

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Record river flooding has been reported in several North Carolina cities and towns, including Chinquapin, Trenton and Manchester, the Weather Channel said.

As rivers swelled, North Carolina state regulators and environmental groups monitored the threat from gigantic hog and poultry farms in low-lying, flood-prone areas.

In all, a wide swath of North Carolina and a small part of South Carolina saw three-day rainfall totals that, on average, would be expected to occur about every 1,000 years, the Weather Underground reported. This means that amount of rainfall has a 0.1 percent chance of occurring in any given year.

The flooding will expand into western North Carolina and Virginia, including potential landslides in parts of the Appalachians, Weather Channel hurricane expert Rick Knabb said.

"We need everyone to be just as afraid of flooding as you would be for the winds of a hurricane or tornado," Knabb said. "Waters are rising in entire communities. If you’re trapped in a flooded building, go to the highest level and call 911."

The storm, which first hit the region last week, will be the USA's costliest hurricane of the year so far: AccuWeather estimated that Florence will cause $30 billion to $60 billion "in economic impact and damage."

By 11 a.m. Monday, Tropical Depression Florence was centered about 240 miles west of Charlottesville, Virginia, and was moving northeast at 15 mph. The Weather Channel said millions of people in the mid-Atlantic and Northeast remain under flash flood watches as the remnant moisture from Florence heads north.

Although the typical peak of the Atlantic hurricane season has passed, officially, the season lasts until the end of November.

Ten tropical storms have formed this season in the Atlantic, five of which have been hurricanes, the National Hurricane Center said.

Contributing: The Associated Press; Christal Hayes, USA TODAY