California Highway Patrol officers were called to Highway 65 near Avenue 184 just before 5:30 a.m. Sunday.
Investigators say a 39-year-old woman veered into the center divide, then over-corrected, causing the car to flip.
Her seven-year-old and 15-year-old daughters sustained major injuries.
The woman was also injured.
They were all taken to Kaweah Delta Hospital.
Drugs or alcohol do not appear to be factors in the crash.