EATONTON, Ga. — A young woman and an 18-year-old senior at Morgan County High School in Madison were killed in a two-vehicle crash on U.S. Highway 441 near Rock Eagle in Putnam County Sunday afternoon, authorities said.

The wreck, which happened shortly before 5 p.m. during a severe thunderstorm, also left three others badly injured, including the high school senior’s mother and 14-year-old brother.

Putnam County Sheriff Howard Sills identified the victims killed in the wreck as Brittany Morgan Smith, 19, and Michael Christopher Rhodes, both of Madison.

Sills said both victims were believed to have died instantly.

Smith and Rhodes, along with Rhodes’ younger brother, Adam, were all passengers in a 2002 Jeep Grand Cherokee driven by the boys’ mother, Tracey Lynn Rhodes, 50, also of Madison, the sheriff said.

The driver of the other vehicle involved in the deadly crash was identified as 21-year-old Kaitlyn Black, of Bethlehem.

Black, along with Tracey Rhodes and her son, Adam, were all treated at the scene of the crash by firefighters/first responders with Putnam County Fire Rescue and personnel with the Putnam County Emergency Medical Services. The three later were taken by ambulances to Athens Regional Medical Center in Athens. When all three victims left the wreck scene en route to the hospital on Sunday, they reportedly were in critical condition.

The sheriff said Monday that the two young survivors were showing signs of improvement, but that Mrs. Rhodes’ condition remained about the same.

The 2002 Jeep Grand Cherokee is believed to have hydroplaned on the rain-slickened highway, Sills said. The jeep traveled across the centerline of the highway near County Line Road 117 before Black’s jeep smashed into it and caused it overturn in the middle of the roadway.

Sills said Monday that the wreck remains under investigation by deputies.