A Pennsylvania high school reverted to virtual classes last week, but it wasn’t because of coronavirus fears. It was because of “credible threats” after student fights.

In a Waldorf, Md., high school, a school resource officer was assaulted as three separate fights unfolded in the hallways and one spilled into the student parking lot. And in a large fight at a high school outside Columbus, Ohio, nine teachers were injured and seven students were charged with aggravated riot.

Much of the attention around the return to school after months of remote learning has focused on academic losses, but educators also feared emotional damage and behavioral unrest as students who have seen their lives upended by the pandemic adjust to being in school buildings again.

Those fears now appear to be materializing, in big ways and small. The National Association of School Resource Officers reports that from Aug. 1 to Oct. 1 this year, there were 97 reported gun-related incidents in schools. During the same span in 2019, there were 29.

Similarly, Everytown for Gun Safety, a lobby group for gun restrictions, tallies 56 instances of gunfire on school grounds in August and September of 2021. That is higher for those two months than any year since the group began tracking incidents in 2013, and more than double the previous high of 22 in 2019. It also found record numbers of deaths, at eight, and injuries, with 35.

“School violence has risen to levels that we haven’t seen quite frankly,” said Mo Canady, executive director of the National Association of School Resource Officers. “I don’t think it took a genius to see this coming.”

There is no national data on less-serious instances of violence in schools, but teachers and school administrators across the country say they are seeing a rise in everything from minor misbehaviors to fighting in the hallways.

“The toxic stress of everything going on during the pandemic, it’s building up with kids — and adults. Now that they’re around each other again, they need to relearn how to do school again,” said Christina Conolly, director of Psychological Services for Montgomery County Public Schools in Maryland, who recently chaired the School Safety and Crisis Response Committee of the National Association of School Psychologists.

Stress levels are also high among adults when it comes to schools, with loud fights over whether masks should be mandatory and over how to teach about race in schools. Some school board members have been shouted down and even threatened by parents angry over school policies.

More worrisome for students, experts say, is the social isolation wrought by the pandemic. Isolation is among the risk factors for students who commit violent acts in schools, the Department of Homeland Security warned in a May bulletin. The agency noted that the pandemic also denied many students access to mental health professionals and put financial strains on many families.

“The reduced access to services coupled with the exposure to additional risk factors suggests schools — and the communities in which they are located — will need to increase support services to help students adjust to in-person learning as they cope with the potential trauma associated with the pandemic response,” the Homeland Security bulletin said.

Anecdotally, teachers and even some students say the level of disturbance this fall has gone far beyond years past. In some cases, students are unaccustomed to following the rules that govern a school building. They don’t grasp the expectations for their ages, teachers say, because the last time some were in school was two grades ago.

Dawn Neely-Randall, a fifth-grade teacher in Elyria, Ohio, has taught for more than 30 years and said she has never seen “so much defiance” from students, including children pushing each other and lobbing verbal attacks.

“I’m not just talking about immature behaviors,” she said. “On the first day of school, when students are usually on their best behavior, they came roaring in, jumping onto and over the furniture.”

She said she has managed to get her classes under control but she has to be stricter than usual, and was pushed to seek anti-anxiety medication for the first time in her life and has begun contemplating early retirement.

“Hardest year in 32 years of teaching,” she wrote in a Facebook post. “I know I’m not alone. It’s being felt all across the nation.”

Leo Cavinder, 17, sees it too, at La Porte High School in La Porte, Ind.

“I have seen and heard a lot more violence … than in previous years,” he said. “There have been fights break out that result in blood on the floor and lockers and broken or bruised faces.”

He blames the extended period of remote school, where students didn’t have to deal with peers. “Students are adjusting back to normal,” he said.

At Westlake High School in Waldorf, Md., the principal wrote families this month about multiple fights in a single day. The first was after lunch in the hallway, then came a second after sixth period, outside the library. As the halls were being cleared, another fight was unfolding upstairs that resulted in a physical assault on a school resource officer.

Then, as school dismissed, a fourth altercation occurred in the student parking lot.

“Please talk with your child about using supports in place at school, and consequences for behavior that violates school policies and rules,” Principal Diane Roberts wrote.

In Lysa Mullady’s elementary school in Suffolk County on Long Island, the behavior problems are small things: “No one can get along on the playground.”

“The remote-learning kids who are coming back into the classroom have forgotten what it’s like to be with other children,” she said. “There’s a skill set that you need to problem-solve.” Those skills include talking it out and walking away, she said. “They haven’t had to navigate outside their homes for so long they’ve really forgotten how to do it.”

Mullady, vice president for elementary for the New York State School Counselor Association, said she advises teachers to go over difficult moments with the whole class, so everyone can learn how to better solve problems. Schools need to examine data and teachers need to consult with each other to identify students who are having trouble. And, she said, teachers need to take time to check in and connect with individual children.

“It’s relationship building, it’s creating safe spaces so you build a relationship by really seeing each child,” she said. “Teachers are feeling the stress of the gap they have to make up academically, but we cannot make up any gap until a child is emotionally ready to learn.”

At a recent meeting of the school board in the Addison Central School District in Vermont, Fawnda Buttolph said she has never seen such poor student behavior in some 20 years of teaching. This fall, she has worked as a substitute in four district schools.

“The kids are in charge and they know it,” she said during a long speech in which she broke into tears. She described disrespectful students refusing to do classwork and “chaotic” hallways.

One day a student threw a bag of grapes into her classroom, making a mess that he refused to clean up. Students in one of her classrooms were so “out of control” and disrespectful that she had to call in the principal, who came with the assistant principal and removed four students. “For the first time ever, I raised my voice and yelled at my students. I’ve never done that,” she said.

In Farmington, N.M., two high school students were arrested for planning a school shooting, after officials found a map and written plans. Separately, Superintendent Gene Schmidt said there was some damage done to a couple of school bathrooms, the result of a TikTok challenge. Other than that, though, he says students have mostly been excited to be back in school.

“After kids had been out of school for so long, when they first came back we had, if anything, less behavioral problems than before because they just wanted to be back in school,” he said.

Other educators say the year began on a joyful note but behavior problems emerged after students were back for a bit.

At Woodland Hills High School outside Pittsburgh, the district shifted to remote schooling for two days in hopes of calming things down after fights rolled through the school last week.

It began with two girls fighting at lunch, said Superintendent James Harris. Later that day, two boys fought over a girl, prompting friends to jump in. By the time it was over, 30 students had attacked other students, he said.

“That adrenaline just started flowing through them and they couldn’t control it,” Harris said.

Harris said he is not excusing the behavior, but has little doubt the mayhem can be traced to students needing to relearn how to be in school after so many months away from it.

“The freshmen were seventh-graders last time they were in school,” he said. “They went from recess and cartwheels to ‘what do you want to be when you grow up?’ and ‘where do you want to go to college?’ Their bodies have grown but their minds haven’t. They’re still seeing themselves as young students who want recess, who want to play.”

At the same time, many students have lost loved ones in the pandemic, and there have been recent shootings in the area, leaving students with added trauma.

“A lot of it comes down to socialization, expectations and I think deep down inside there’s a lot of sadness from the trauma that students experienced,” Harris said.

He decided to move to remote school last Thursday and Friday after administrators picked up comments on social media threatening to continue the fight. After two days of remote learning, he said, Friday night’s football game and Saturday’s homecoming dance went on as scheduled and unfolded without any trouble.

Harris said the two-day break was made possible by technology bought for remote school during the pandemic. He had imagined the schools might also use it on snow days, or for a student who was out of town.

“It’s a tool that we have at our disposal,” he said. “We never thought we [would have to] shut down the school because of kids fighting.”