The five teenagers killed in one of the deadliest car crashes in Newport Beach history left behind a sense of "unimaginable loss" in the Irvine Unified School District, where they were all students.

Two of the dead were sisters. And some of the five also had siblings in the district, officials said.

"There are simply no words to convey the sorrow felt by our staff and our students and our community, and nor are there sufficient answers to explain the loss of these vibrant young teenagers," Irvine Supt. Terry Walker said at a news conference Tuesday. "I'll just tell you, as a superintendent, there isn't anything more profoundly tragic than what we've experienced today."

Among the victims were sisters Robin, 17, and Aurora Cabrera, 16 — a senior and sophomore, respectively, at Irvine High School .

The driver, Abdulrahman Alyahyan, 17, was a senior at University High School, while the other two passengers — Nozad Al Hamawendi, 17, and Cecilia Zamora, 17 — were juniors at Irvine High.

The group was riding in a 2008 Infiniti sedan Monday when it veered off Jamboree Road and plowed into a tree on the median. The luxury car was split in half, and when Newport Beach firefighters arrived at the site of the crash just north of Island Lagoon Drive at about 5:20 p.m., one part was engulfed in flame, authorities said.

Four of the teens were pronounced dead at the scene and one died a short time later at Mission Hospital Regional Medical Center.

Ida Lodriguito, step-grandmother to the Cabrera sisters, told the Los Angeles Times they were "very loving and caring girls" who were "raised in a nurturing atmosphere," adding that they had died "so close to becoming adults."

The girls' uncle, Bernard Cabrera, told The Times that they appeared shy at first and had big hearts.

"Their dad could never say 'no' to them," he said. "How could you — they were always so sweet."

As details of the crash emerged, members of the community took to social media to mourn the loss of young people whom friends described as understanding and fun-loving.

A friend with the Twitter handle @jescadorka tweeted that she "only knew Cecilia" but that she was "such a crazy, down to earth girl! She always had someone laughing."

"[S]he was such a caring person ... the locker room for dance will never be the same," a friend with the Twitter handle @craminator tweeted, apparently of Zamora. .

Many posts mentioned a girl named "Christine," along with Zamora and Robin Cabrera, seemingly in reference to Aurora Cabrera.

"Rest in peace Cecy, Christine, and Robin," wrote @isaiahcrawley82 on Twitter. "You're in a better place now and God will take care of you all."

On Instagram, @tara__jaff wrote of Al Hamawendi: "You were always like a brother to me, got mad at whoever messed with me even if they were joking."

A few classmates also visited the scene of the crash Tuesday, where ripped-out grass on the road's median tracked the car's path to the tree — still standing, but with its bark stripped bare.

Aram Yaco, 17, remembered Al Hamawendi as someone who went out of his way to lend a kind word to strangers.

"You never saw that guy frown once," he said.

Classmate Kelly Dunkle echoed classmates' comments online in describing Zamora, commonly known as "Cecy," who she said had a bubbly personality and was "one of the happiest people you'll ever meet."

"It was funny when she tried to be mean because she couldn't," she said.

At the news conference, Walker stressed that help will be available for any classmates whose struggle to grasp the scope of the tragedy might be more internal.

Tuesday was a staff development day, which meant that there was no school and teachers and staff had more time to prepare for an announcement to students Wednesday.

Counselors and psychologists will be on campuses and will reach out to students who were close to the victims, he said.

"If [students are] going through something, they need to let someone know," he said.

Los Angeles Times staff writer Christopher Goffard and Daily Pilot online editor Kelly Parker contributed to this report.