The CHP says investigators think the other nine fatalities were all people riding on the bus, but have not yet confirmed whether they were all teenage students.
Around 5:30 p.m. Thursday the FedEx truck, carrying two trailers, crossed a grass median and swerved into the northbound lanes. It sideswiped a little white car that was directly in front of the bus and then hit the bus head-on. Both vehicles burst into flames.
Investigators said they think the truck driver might have been trying to avoid a passenger car that was also involved in the crash.
The tour bus had 46 people on board, 42 of them were students from a few Los Angeles high schools. There were three chaperones and one driver on the bus. Many of the injured appeared to be bleeding and were in shock. Others were seen limping around the wreckage before they were taken to hospitals in Chico and Redding.
A student called her mother, who alerted the Los Angeles Unified School District officials.
Gov. Jerry Brown issued a statement on the crash Thursday evening saying in part, "Anne and I extend our heartfelt and deep sympathies to the families, friends and loved ones of those who died in the tragic accident near Orland this evening."
Bonnie Kourvelas, a FedEx spokeswoman, said in a statement Thursday night: "Our thoughts and prayers are with everyone involved in the tragic accident on I-5 in California. We are cooperating fully with authorities as they investigate."
The National Transportation Safety Board is sending a go-team to investigate the crash. A CHP investigation has been ongoing since the crash happened and they expect to have that portion of I-5 closed until 7 a.m. Friday. Vehicles are being diverted over to Highway 99.
Families of students who may have been affected may contact Humboldt State University Police for more information at (707) 826-5555 or use the Red Cross Safe and Well website to locate students.
Stay with abc7news.com for updates on this developing story.
Photo courtesy of Tyler May/KRCR.
The Associated Press contributed to this report.