The crash happened just after 5 a.m. The cause of the accident is unclear, but one car was left overturned on the roadway, and some victims were ejected, police said.
According to CHP officer Adriaan Garcia, the fatalities include a 42-year-old woman and an 11-year-old girl. Both victims were declared dead at the scene. Their names have not been released.
Four people were rushed to a local hospital by helicopter in critical condition. Three of them are children. Two other people were transported to a local hospital by ambulance in unknown condition.
All southbound lanes were closed for more than two hours.
The accident remains under investigation.