(CNN) -- Jonathan Gutierrez kicked off his shoes and dozed off in the back of a bus traveling along a sleepy stretch of Interstate 5 near the North California town of Orland.
The trip to Humboldt State University was meant to open doors and possibilities for 17-year-old Gutierrez and dozens of other teens, all low-income or first-generation prospective college students.
It ended Thursday with at least 10 people dead and 30 injured in a fiery wreck 90 miles north of Sacramento, when a FedEx truck crossed a median and slammed head-on into one of three buses taking the teens to Humboldt State University.
"I was asleep and next thing you know I was jumping out for my life," Gutierrez wrote in a Twitter post in the minutes after the crash.
In another post he wrote: "Bruised leg, eyebrow cut open, scratches all over my arm. ...All my stuff that I packed is burned. I'm beyond thankful that I'm still here."
The collision killed both drivers, five students and three chaperones, Lt. Bruce Carpenter of the California Highway Patrol said Friday.
More than 30 people, primarily teenagers, were taken to local area hospitals for injuries.
Identifying the dead
"Many of them had cuts, contusions, bumps, minor burns. I know there was one person when we arrived on scene that was on fire," Officer Tracy Hoover of the California Highway Patrol told CNN affiliate KRCR-TV of Redding.
The Sacramento County Coroner's Office identified one of the victims as 26-year-old Arthur Arzola, an admissions counselor and recruiter at Humboldt State.
Arzola was based in the Los Angeles area and considered the university like family, according to his profile on the school's website.
He described himself in the profile as "hard-working, thoughtful, compassionate and friendly."
Arzola died at the hospital. Officials said it is a bigger challenge to identify those who died at the scene of the crash, partly because many suffered burns.
Dental records will be used to identify some of the bodies, Glenn County Chief Deputy Coroner Richard Warren said. If it is not possible to do it that way, officials will use DNA, which would be a longer process, he added.
Investigators are looking into the cause of the accident, which occurred at about 5:45 p.m. local time Thursday on Interstate 5, the main north-south thoroughfare that cuts through heart of California's farming country, in Orland.
Eyewitnesses have told investigators that the FedEx truck sideswiped another car before crashing into the bus. The two occupants of that vehicle were not seriously injured but were sent to a hospital for treatment.
"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," FedEx spokeswoman Bonnie Kourvelas said.
NTSB agents en route
The reason the FedEx truck crossed the median remains under investigation, the CHP said. The investigation could take months, and the National Transportation Safety Board announced Friday that it is sending a team to investigate as well.
"One, we're going to be investigating the human, the machine and the environment, and what's critical for us especially in highway accidents if for us to collect perishable information, the kind of information that goes away very quickly," NTSB Member Mark Rosekind said.
"And then the most important thing we can do is issue recommendations so that these kinds of accidents don't happen again," he said.
Authorities were working Thursday to reunite parents with the surviving teens who were aboard the bus.
The more-than-40 teens, who represented 31 different Southern California high schools, were heading to "Spring Preview Plus" -- a two-day trip that invites low-income and first-generation prospective students to Humboldt State's Arcata campus.
As part of the program, students stay in residence halls, attend events and visit with staff and students from a program that helps historically underrepresented students, the university said.
The two other buses in the caravan made it to the university, and those students were placed in dorms, Humboldt State officials said.
The university is offering counseling to those students.
'Can't believe this happened'
Some on the trip, such as Gutierrez, had already been accepted to the university. Others were still in the application process or still trying to make up their minds.
Gutierrez, like many of the others, was clearly excited about the trip. He posted photos of the journey. There were snapshots of stops in Fresno and Sacramento, and one he took from the back of the bus that showed students relaxing.
But it is the photos and comments that followed that were harrowing. A snapshot of black billowing smoke from the burning bus, and then the post: "I can't believe this."
Gutierrez also posted snapshots of himself in the hospital as a way to assure friends and family he was OK.
"Seeing everyone hurt was not how (I) expected my day to go," he said.
CNN's Jackie Castillo, Augie Martin, Dave Alsup and Tina Burnside contributed to this report.