Earlier Wednesday, Marion County Coroner Jerry Richardson had identified Newton with a different last name. Richardson says the women were being transported from a hospital in Horry County to medical facilities in Florence and Darlington.
Because of darkness, responders decided trying to retrieve the women's bodies from the van Tuesday night wasn't safe.
"Tonight's incident is a tragedy", Thompson said.
Horry County Sheriff Phillip Thompson told reporters on Wednesday that 45-year-old Windy Newton and 43-year-old Nicolette Green were in the back of a containment van when rising waters carried it off the road Tuesday night in Marion County.
Two women who were being transported to a mental health facility drowned when a sheriff's department van was swept away in rising SC floodwaters, according to authorities. Flood stage for the Little Pee Dee is 9 feet.
Officials said that the van was near the Little Pee Dee River, one of the bodies of water that state officials are watching following the heavy rains of Florence.
The two women have not yet been identified. The sheriff's press release says that the deputies tried to save the lives of Green and Newton.
Rescue teams were able to save the deputies from the van's roof, but they could not pull the vehicle from the water because it was too risky, according to the release.
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South Carolina Law Enforcement Division Spokesman Thom Berry said recovery efforts are set for today - the van and the victims remain in the flood waters at the scene.
A woman who answered the phone at a number listed for Flood told a reporter he didn't want to talk to anyone.
Asked how the women were restrained in the back of the van, Fox told CNN they were "seat belted".
"I know that it is a very sad situation so ive just been praying for the victims and the families of the victims", said Martin. It could have been water pressure or the way the van was resting against a guard rail, he said.
We are now working with the SCDNR to recover the vehicle. By the time they got there, the van was underwater, and the deputies were on the roof.
We are working hand-in-hand with the State Law Enforcement Division to cooperate in this investigation.
The officers involved in the incident are placed on administrative leave.