A day after a once-in-a-thousand-year rainstorm, southern Appalachia faces Hurricane Helene

A rainstorm expected only once every 1,000 years deluged parts of southern Appalachia on Wednesday night, with as much as 8 inches falling in a day’s time in Asheville, North Carolina.

Now, the area awaits some of the most intense rainfall forecast from fast-moving Hurricane Helene. In some areas, Helene could dump an additional 6 to 12 inches of rain, according to the National Hurricane Center.

“We’re expecting unprecedented rainfall amounts in a two- to three-day period,” said Andrew Kimball, a National Weather Service forecaster in the Greenville-Spartanburg, South Carolina, office, adding that forecasters expect rivers to flood at record levels.

“In addition to the rivers flooding, that much rainfall will also likely result in widespread landslides in the mountains and each large debris flows where the whole side of the slope fails and it becomes almost like a liquid and washes down. Those impacts are expected to really ramp up tonight.”

Kimball said tornadoes are possible. Wind gusts could reach hurricane strength at hilltops. Trees are expected to fall and cause power outages.

The forecast illustrates how the hurricane’s impacts will not only be felt in coastal regions but also reach deep into the heart of the Southeast. Asheville is nearly 400 miles from Florida’s Big Bend, where the hurricane is expected to make landfall Thursday night.

In the Asheville area, local officials urged people to leave low-lying areas.

“It’s possible we may get to a point where our crews will not physically be able to perform rescues,” Buncombe County Emergency Services Director Taylor Jones said in a news release. “We cannot emphasize how much you should take this seriously.”

The University of North Carolina Asheville canceled classes Thursday afternoon. The local school district closed its doors Thursday and Friday. Roadways were flooded and closed Thursday.

“The tropical system isn’t even here yet, so you can understand there’s a lot of concern here,” said Christopher Godfrey, a professor and chair of the department of atmospheric sciences at University of North Carolina Asheville.

Godfrey said the rain overnight Wednesday was driven by a rare precursor event, when a front stalled over the region and funneled moisture pushed north by the tropical storm.

“If we didn’t have the tropical system, we would still have a rainy day,” Godfrey said. “But with the tropical system developing, that is also enhancing the southerly flow that’s bringing in this moisture.”

In 1916, 25 people died after flooding devastated western North Carolina and swept away entire buildings after the remnants of tropical storms led to extreme rain, according to the Asheville Museum of History. Friends and family members watched as loved ones were swept downriver. The local power plant was destroyed, and the railroad was badly damaged, cutting Asheville off from the rest of the world.

Buncombe County officials warned that flooding over the next few days could rival or exceed the events of 1916.

This article was originally published on NBCNews.com