Officials said that at around 7:40 p.m., a "big rig hauling trailer" going northbound on I-5 signaled and started to merge into the left-hand lane, directly into the side of a Chevy Suburban carrying six people.
The Suburban lost control and swerved left while trying to avoid the big rig. Traffic officials said that it then crossed the center divider and continued into the southbound lanes, driving perpendicular to the flow of traffic.
The Suburban went directly in front of a southbound Toyota 4-Runner carrying the Granados family. The front of the Toyota crashed into the right side of the Suburban, police said.
Highway patrol officials said that three of the occupants of the Suburban died in the crash. Two of those people were adults, the third was a 7-year-old child.
A 14-year-old passenger also inside sustained major injuries. The other two passengers, ages 10 and 15, received moderate injuries.
Five passengers of the Toyota 4-Runner all sustained major injuries. Police said that a sixth person inside the 4-Runner, 8-year-old Jaqueline Granados, sustained moderate injuries.
Everyone involved in the crash was wearing a seat belt during the impact.
Officials said that they have opened an investigation into finding the driver of the big rig. Anyone with information into the crash is asked to call Officer Ken Antonetti at (559) 935-2093.