The first tornado was spotted by ham radio operators about 5:25 p.m. Sunday as it formed from a wall cloud in Columbia County.
It touched down across the river in Edgefield County, according to National Weather Service meteorologist Steve Naglic.
The EF1 storm, with winds up to 110 mph, was probably on the ground for about two minutes, striking a mile-long path from Woodlawn Road north into Sumter National Forest, Naglic said.
A second tornado also touched down in Edgefield County, just south of Garrett Road at Martintown Road about 10:30 p.m.
This EF2 storm, with winds estimated at 115 mph, tore the roof off a home, sent trees falling onto a house and motor home and downed or snapped the tops of many more trees, Naglic said.
Its path a quarter-mile wide, the tornado was on the ground for three miles, he said.
The same storm touched down again in Batesburg-Leesville, S.C., where it was on the ground for six miles, damaging several homes and causing one minor injury, he said.