Former Columbine High School principal Frank DeAngelis is among those offering support for students in Parkland, Fla., as they return to classes at Marjory Stoneman Douglas High School on Wednesday, two weeks after a former student opened fire and killed 17 classmates and staff members.

"It brought me back to April 20, 1999. When I saw the images of the students running out the building with their hands over their head, those were my students, Columbine students . . .it had a deep impact on me," DeAngelis said.

As students return to a vastly different school setting – one that’s encompassed by police cars, media, law enforcement officers, and counsellors – DeAngelis shares advice that he learned after the Columbine massacre: it’s time to redefine normal.

"I really believe that people who go through tragedies such as they are at Stoneman Douglas High School, they feel that one morning they’re going to wake up and everything’s going to be back to the way that it was prior to the tragedy . . . and that just doesn’t happen," DeAngelis told CTV News Channel in a video call on Wednesday. "We learned at Columbine that we had to redefine what normal is, that it would never go back to the way it was prior to the shootings occurring."

Recovery will be a lifelong process, DeAngelis said – one that some of his former students continue to struggle with, 19 years after two student gunmen opened fire at Columbine High School, killing 13 students.

"Where it really affected many of them is when they had their own kids,” DeAngelis said. “Many of the students who were at Columbine during that horrific time now are married and they have children, and when they had to send their kids to school, they thought back to what it was like on that day."

DeAngelis said the struggle was much more difficult for the Columbine students who were in Grade 12 in 1999. Senior students had little time – about a month – before they graduated and headed out into the world “on their own,” DeAngelis said, which won’t be the case for students returning to Marjory Stoneman Douglas.

"In the class of '99, I refer to as ‘the lost class,’ because many of them went off to college, many of them went starting their careers, and they didn’t have the support,” DeAngelis said. 

But for those who returned to Columbine – staff members, and students who graduated in subsequent years – there was a “great support system in place,” DeAngelis said.

"Fortunately, the senior graduating class in Parkland will have time to deal with some of these issues before they go off, which I think will be very beneficial,” he added.

As for the ongoing debate about gun control legislation, DeAngelis said one thing is clear: “arming teachers is not the answer.”

"The day that the Columbine tragedy happened, I came out of my office and I was confronted by the gunman. If I would’ve been able to carry a weapon on that particular day, even though I am trained at target practice and different things, I’m not sure if I could’ve shot the kid, because he was one of my students," DeAngelis said. 

"As an educator, so many times we try to counsel, we try to take care of kids, we try to listen, and if that would’ve been the case, there were 30 girls coming out of a locker room into the hallway. If they were depending on me to stop that killer, I’m not sure if I could’ve pulled the trigger, and if I could not have done that, I could’ve very easily have put those girls in harm’s way," he added.

"There’s more to it, it’s a mental frame of mind. . . . for educators, I think it’s going to take much more than just putting a gun in their hand."