Brush fires erupted in both North Carolina and South Carolina on Saturday, forcing officials to order evacuations.

A fire in Polk County, North Carolina, was burning at least 400 acres and was at zero containment as of late Saturday night, the North Carolina Fire Service told CBS News. He said structures could be at risk and officials would examine potential damage on Sunday morning.

Polk County urged residents along U.S. Highway 176 between the towns of Tryon and Saluda to evacuate, warning on Facebook that the fire was spreading rapidly as multiple fire departments worked on containment. Tryon and Saluda are about 40 miles south of Asheville.

Horry County Fire Rescue ordered the evacuation of residents from several neighborhoods in the Carolina Forest. (Horry County Fire Rescue)

A red flag warning from the National Weather Service expired late Saturday night for western North Carolina and upstate South Carolina. Red Flag warnings mean critical fire weather conditions are either happening or are about to happen.