The accident happened at 1st and Sullivan streets at about 9 a.m. Authorities say it appears the driver of a Nissan Altima, a 65-year-old man, ran a red light at Sullivan Street, slamming into a Nissan Infiniti. The Altima then crashed into a light pole and a tree.
"It just sounded super loud, like two bombs exploding," said Elizabeth Melchor of Santa Ana.
The front passenger of the Altima, a 78-year-old woman, was declared dead at the scene.
The driver of the Altima and two other female passengers were rushed to area hospitals. The driver of the Infiniti, a 22-year-old woman, was also rushed to an area hospital. There were no other people in the Infiniti.
Police say all the injured were trauma patients. They are now in stable condition.
The accident remains under investigation.