Sandy Austin was in her second year working as a school counselor in Colorado in 1999 when two students opened fire at Columbine High School in Littleton, killing 12 of their fellow students and a teacher before turning their guns on themselves.
Responding to a district-wide call for counselors, Austin drove to a nearby elementary school where parents and caregivers were gathered to hear whether their children were alive. She spent the next nearly 10 months counseling students, teachers, school staff, parents and community members in the wake of the shooting.
On Tuesday, when a gunman burst into Robb Elementary School in Uvalde, Texas, and killed at least 19 children as well as two adults, Austin said she immediately thought of the mental health support that the survivors, parents, teachers and community will need in the days, weeks and years ahead.
"It takes me right back to that day at Columbine," Austin, who later worked as a crisis facilitator for the American School Counselor Association (ASCA), told "Good Morning America" in a recent interview. "I think of those little ones, all their life, they're going to need that counseling. It'll always be hanging over those kids."
Among those killed were a pair of fourth-grade teachers who were longtime staff members at Robb Elementary School. The 19 slain children were students aged 10 and 11, including several who were cousins.
Tuesday's massacre was one of the deadliest school shootings in U.S. history. While public attention in the aftermath of such a tragedy may turn to the school's security plan or the local law enforcement response, mental health experts like Austin say the attention for them turns to the mental health plan that every school should have in place. This includes ensuring teachers and staff know how to talk to students about the trauma they just suffered in a developmentally appropriate way and having extra counselors ready to help, Austin said.
Austin noted at the time of the Columbine shooting, there was no real plan in place for how to help the school community cope.
In the two decades since, as the number of school shootings has risen dramatically in the United States, more schools now have plans in place. But, sadly, it's become overwhelming for schools to try to keep pace with the growing scale of crises, according to Dr. David Schonfeld, a developmental behavioral pediatrician and director of the National Center for School Crisis and Bereavement at Children’s Hospital Los Angeles.
"I'm finding that the response is getting better, but the challenge is getting harder," Schonfeld told "GMA," explaining that shootings today "generally overwhelm any plan that’s in place with the resources that any school or district has."
Schonfeld was one of the first mental health professionals on site in the wake of the 2012 shooting at Sandy Hook Elementary School in Newtown, Connecticut, in which 20 children and six adults were gunned down. Less than six years later, Schonfeld helped a grieving community in Parkland, Florida, where a gunman shot and killed 17 students and staff members at Marjory Stoneman Douglas High School in 2018.
In the immediate aftermath of both the Sandy Hook and Stoneman Douglas shootings, grief counselors were made available to the school community, as they have also been in Uvalde after Tuesday's shooting, according to local ABC affiliate KSAT-TV.
The work of the grief counselors, according to Schonfeld, is to listen to kids and adults alike, to validate their feelings, make them feel as safe as possible and support the community as it moves from a state of shock to realizing the permanency of the event.
"When I arrive in communities, one of the first questions I get is: 'When we will go back to normal?' And I say: 'You will never go back to what you were. We don't go back in time. We don't forget life-changing events,'" Schonfeld told "GMA." "It will change the community. That doesn't mean they're permanently damaged, it just means they're altered."
They will never go back to a childhood that didn’t have a mass shooting.
"The kids who are in the community are forever changed," he added. "They will never go back to a childhood that didn’t have a mass shooting. That will define them."
Austin said her grief counseling role in the immediate aftermath of the Columbine shooting was to bring water to parents to help them with the task of taking care of themselves.
"Everyone is just in a daze," she said. "People don’t know what to think. They’re so shocked."
As time goes on, a community like Uvalde will likely focus on bringing in mental health professionals who can offer support for the long-term, according to Schonfeld.
"Usually there is an outpouring of volunteers that want to assist and provide support, but that also has its own issues because you end up with a turnover of these volunteers so children may be talking about their distress and then going back and having to talk with someone else," he said. "When we come, we try to provide systems-level solutions."
MORE: What we know about the victims of the Texas school shooting in Uvalde so farIn Parkland, grant funding allowed Broward County school officials to hire over 100 mental health professionals after the 2018 shooting, according to Rachel Kusher, a counseling specialist at Stoneman Douglas who was hired through the grant.
The newly-hired counselors were sent not just to Stoneman Douglas, where the shooting took place, but also to the five elementary schools and two middle schools that feed into the high school.
"At the high school, we had three full grade levels here that had been on campus the day of shooting. We had students who were injured in the shooting, we had siblings," Kusher told "GMA." "And then at the middle and elementary schools, a lot of students were on what we call 'code red' during the event, so a lot of those students also had been traumatized or had siblings that were here on campus at [Stoneman Douglas] the day of it, or neighbors, family members."
"The difference between the shooting that occurs at a school versus a shooting that might occur elsewhere is that kids don't really have a choice whether or not to come back -- and the same thing for teachers," she added. "They have to return to the site of the trauma."
Recovery for survivors of school shootings may present multiple complications, according to a research analysis published by the American Psychological Association (APA). Research shows students may experience survivors' guilt and post-traumatic stress disorder (PTSD), and they may also struggle with grades and school attendance.
Kusher said that after the Stoneman Douglas shooting, counselors used a tiered-approach to reach students based on their need. At the most basic level, counselors went into classrooms at all eight schools to talk about resiliency and coping strategies.
For students who were on campus the day of the shooting, counselors helped on a more one-on-one basis with reactions like anxiety, PTSD, avoidance of school and making accommodation plans for students who wanted to, for example, sit in a certain seat in a classroom based on their experience that day, according to Kusher.
Students who were directly impacted by the shooting -- whether through injury or the death of a loved one, friend or teacher -- received even more direct attention.
"A lot of what I did personally as their school-assigned counselor was just really helped them with anything they needed, sit with them, sit with their family," Kusher recalled. "They all have my personal cell phone number. They know how to reach me, and I still am in contact with a lot of them."
Mental health counselors also provided long-term support for parents of students as well as for teachers and staff members across the school district. They also had to implement new ways to do things like fire drills and shooter response drills so that students would not be re-traumatized, according to Kusher and her colleague Tonia Summers, a middle school-level school counselor.
"What we found is, like a year later, people were now having different types of issues with PTSD. So for some it was right away, for some it was a few months and for some it was a year," Summers told "GMA." "There were all different levels of trauma that were happening and you have to be on top of all of it."
MORE: How to talk to kids after 19 children, 2 adults killed in Texas school shootingOver the past four years, part of the job of counselors across the Broward County School District has also been responding to a "huge uptick" in 504 plans -- support plans schools develop for students with disabilities -- due to a sharp rise in anxiety diagnoses, according to Christine Ross, a school counselor who works with the elementary schools that feed into Stoneman Douglas.
And when another school shooting happens, like the one on Tuesday, counselors nationwide brace for new mental health traumas.
"It's almost like ripping a Band-Aid off. It takes you right back to being there," Ross told "GMA." "You never know what the students are going to be like when they walk through the doors."
Summers agreed, adding: "When you have dealt with some type of trauma, you’re more susceptible to other types of trauma, so something like this happens and they’re retraumatized again."
The long-term and far-reaching effects that a school shooting can have on survivors were seen tragically three years ago, when a Stoneman Douglas student, a former student and the father of a Sandy Hook victim each died by suicide within the span of a few weeks in 2019.
Even in schools across the country where shootings are not part of their past, counselors responded to support students in the wake of Tuesday's massacre, showing the even wider ripple effects a mass trauma can have.
"If there's a big traumatic national event, like a school shooting, school counselors know to make themselves available and that's what is happening," Olivia Carter, a school counselor support specialist for Cape Girardeau Public Schools in Cape Girardeau, Missouri, told "GMA."
"It really digs into a deep fear for a lot of people," she added. "There’s a lot of fear and a lot of dysregulation, and there’s a need to have resources available."
For Kusher and other counselors who have lived through a school shooting or its aftermath, they said they want those in Uvalde to know that they are there for them and are supporting them.
"Those school counselors at Robb Elementary School need to help themselves too," Kusher said. "They're part of this club that nobody wants to be a part of."
