Up to 7 inches of rain fell in some parts of the state overnight on Monday, leading to supercharged flooding.
First responders were initially able to rescue the mother and one of the children, but fast-moving water capsized the recovery boat and the child slipped away. Both children remain missing.
"They got into the water and they were able to rescue the child, a child and the mother," said Smithfield Fire Chief John Blanton. "The water was so turbulent that the boat capsized. And they lost the child. They were able to regain the mother."
According to Blanton, a total of four swiftwater rescue boats capsized in the extreme current. Rescuers have since found the mother's car, but no sign of the two children. Rescue efforts have expanded and searchers are now using a helicopter to look for the missing kids from above.
Johnston County Sheriff Steve Bizzell announced Tuesday evening that the search for the children has been suspended for the night and will continue as a search and rescue mission at 7:30 a.m. Wednesday, according to ABC affiliate, WTVD.
Not far from the scene of the missing children, an elderly couple was rescued after their car overturned on a rain-slicked I-95.
Witnesses who saw the accident sprang into action and helped them. Neither appeared to be seriously injured.