School shootings are more common than you may think: A look at the incidents that went under the radar in 2019 ABC News found that 57.6% of school shootings were at sporting events.

School shootings are a nightmare scenario for parents, students and teachers alike -- and a national scourge that seems to have no end.

Since Columbine permanently etched horrific images into the national consciousness two decades ago, the scene has played out again and again. And school districts around the country have girded themselves against that dreaded scenario, performing drills, hiring armed guards and preparing safety plans.

According to the FBI, there have been 42 "active shooter" incidents at Pre-K through 12 school grounds from 2000-2018, which the bureau defines as "an individual actively engaged in killing or attempting to kill people in a populated area." These include the high-profile incidents like Parkland and Sandy Hook.

But this definition obscures many school shootings -- more than two dozen in 2019 alone, according to an ABC News analysis of incidents at K-12 schools -- many of which pass under the radar, but impact the students, teachers and communities where they occur.

School shootings represent just a tiny fraction of the firearm crimes in the United States -- there were more than 185,000 aggravated assaults with a firearm in 2018 alone, according to FBI data -- but their impact is "devastating for families, schools, and entire communities," according to the Centers for Disease Control and Prevention. And beyond any physical injuries suffered, children exposed to violence can suffer "a wide array of negative health behaviors and outcomes, including alcohol and drug use and suicide," the CDC said.

During the third week of November alone, officers responded to crime scenes on the East and West coasts: in Pleasantville, New Jersey, where a 10-year-old child was killed during a football game, and in Santa Clarita, California, where a teen opened fire on his classmates, killing two and wounding several more at Saugus High School.

With no nationally accepted definition, sorting out what constitutes a school shooting is difficult. Everytown, an independent, non-profit group that studies gun violence, reports it has tracked at least 99 incidents of gunfire on school grounds in 2019 alone (through Dec. 11), including three suicides and 63 injuries.

The CDC tracks "school-associated violent deaths," which it defines as "a violent death (i.e, homicide, suicide, or legal intervention) that occurs on school property, on the victim’s way to/from school, or at or on the victim’s way to/from a school-sponsored event." In the 2015-2016 school year, there were 18 such deaths, the agency said.

ABC News has reviewed the database from the non-profit Gun Violence Archives, and, for the purposes of this story, defined a school shooting as an incident where an alleged assailant steps onto the property of an educational institution -- during school hours or during an extracurricular activity on the property -- and fires a gun at another person, in order to present a fuller picture of violence at schools not covered by the FBI "active shooter" rubric.

Based on news reports and data collected by the Gun Violence Archive, ABC News has found 26 such shootings since January -- with half occurring on Fridays. The most violent month was in September, where seven shootings were reported at high schools in Pennsylvania, South Carolina, Texas and Virginia. July was the safest month, according to ABC News' report.

Among those more than two dozen incidents, six people were killed and 44 were injured. ABC News did not include the alleged assailant in its data.

The analysis also found that the majority of incidents -- 57.6% -- were at the end of or during sporting events, specifically basketball and football games.

Here are the incidents so far in 2019:

Friday, Jan. 25: Mobile, Alabama

At Davidson High School, a 17-year-old boy and a 20-year-old man were shot and injured after a basketball game. Both of the injured did not have life-threatening injuries. The 15-year-old alleged shooter, who was charged as juvenile, and his 46-year-old mother, LaSandra Dortch were arrested. Dortch was charged with trying to hide her son from the police and her son was charged as the alleged shooter. The mother was in court on Nov. 5 and pleaded not guilty to the second-degree hindering prosecution charge, said Nancy Manlangit, a spokesperson for the Mobile County District Attorney's Office. Information about the alleged juvenile offender's case was not made public.

Friday, Feb. 8: Baltimore, Maryland

Neil Davis, the 25-year-old brother of a student at Frederick Douglass High School, allegedly shot Michael Marks, 56, a special education assistant, in the lobby of the building for "taunting" his 16-year-old sister, his mother told WBAL. Marks, 56, was shot twice and taken to the hospital in serious, but stable condition. Davis, 25, was arrested by Baltimore City School Police Department officers who were working inside the building at the time. Davis pleaded not guilty to the charges, which include attempted murder, according to court records. He's expected back in court on Feb.18, 2020. Davis' mother reportedly said he suffers from mental illness and is not a "monster."

Tuesday, Feb. 12: Kansas City, Missouri

After a girl's basketball game at Central Academy of Excellence, 15-year-old Anjanique Wright was walking out of the building when she was hit by gunfire. Jamya Norfleet, 21 and Taylor McMillon, 18, were arrested for Wright's murder. It is not clear if they entered pleas. Both are set to stand trial, according to court records. According to a spokesperson with the prosecutor's office, Norfleet is scheduled to go to trial in October 2020 and McMillon is scheduled for trial in March 2020.

Thursday, Feb. 14: Rio Rancho, New Mexico

A 16-year-old student was charged with three counts of attempted murder after opening fire inside Sue Cleveland High School, almost a year after threatening to commit a school shooting. No one was injured. The teen's parents were also charged with with fourth-degree contributing to the delinquency of a minor. They were allegedly aware of his prior school shooting threat and did not properly secure their handgun from him. The student suffers from mental illness and has not been found fit to proceed with trial, according to a spokesman with the prosecutor's office. His parents have filed motions to get their charges dismissed and to change the venue according to the spokesman. The parents have all entered a plea of not guilty.

Tuesday, Feb. 26: Montgomery, Alabama

Michael Woods, 17, allegedly shot another 17-year-old student in the arm inside the gym of Robert E. Lee High School, which has metal detectors. The school was placed on lockdown and police said the shooting appeared random. Woods was charged as an adult with attempted murder and weapons charges. Three other weapons were found in the building that same day. A spokesman for the prosecutors said that Woods' case is still pending and entered a not guilty plea.

Monday, April 1: Prescott, Arkansas

A dispute between two middle school students spilled into the hallways of Prescott High School and one student shot another. A 14-year-old middle school student was shot and was airlifted in stable condition to a hospital in Little Rock. The school went on immediate lockdown and the alleged shooter was taken into custody. The middle and high school share the same campus. A spokesperson with the Nevada County Circuit Court told ABC News that juvenile cases are not public record.

Tuesday, May 7: Highlands Ranch, Colorado

Devon Erickson, 18, and Alec McKinney, 16, allegedly opened fire into two classrooms inside STEM School Highlands Ranch. Kendrick Castillo, an 18-year-old student died and eight other students were injured. The school is located 7 miles away from the scene of the Columbine High School massacre where 13 were killed and 21 were injured in 1999. Both were charged as adults with murder and attempted murder and as of September, neither alleged gunmen have entered pleas.

Wednesday, May 8: Chicago, Illinois

A 19-year-old student was shot in the neck and jaw as he and his two friends were leaving school. Andres Salazar, 18, was arrested and charged with attempt first-degree murder, aggravated battery and aggravated discharge of a firearm for shooting the student as he was driving by Second Chance High School.

Friday, May 17: Jacksonville, Florida

With four minutes left in a high school football game between Terry Parker and Raines high schools, shots were fired in the parking lot. Shamon Micken, 16, a student of Raines High School was shot and 19-year-old Arthur Davin Jones III was arrested days later in Georgia. Jones III was charged with attempted murder and pleaded not guilty. He is expected in court on Jan. 15 for a pre-trial conference, according to a spokesman with the state's attorney for Duval County.

Friday, June 21: Flint, Michigan

During a basketball competition inside the gym of Carman-Ainsworth High School a brawl reportedly ensued involving dozens of people. Shots were fired and 15-year-old Eithan Williams hit in chest, the report said. The bullet lodged to his lung and he was hospitalized for days. Williams' doctors told ABC12 that he is "lucky to be alive." Four teenagers, aged 14 to 16, were arrested.

ABC News found that 57.6% of the shootings were at the end of or after sporting events, specifically basketball and football games.

Friday, Aug. 23: St. Louis, Missouri

During a football game at Parkway North High School a series of fights broke out outside the school when a shot was fired. No one was injured and no arrests were made.

Friday, Aug. 30: Toledo, Ohio

As spectators were leaving a football game at Central Catholic High School, a 16-year-old boy was shot by another teen. Neither of the individuals involved with the shooting attended Central Catholic of Springfield High School and there was no altercation before the shooting, police said. No arrest were made.

Friday, Aug. 30: Kinston, North Carolina

As police were attempting to clear the parking lot of Kinston High School after a football game, Ni'yon Lathon and Rahmel Gray allegedly fired shots into the air. Lathon, 17, and Gray, 19, neither of whom are students at Kinston, were arrested. No one was injured. Lathon was charged with possession of a weapon on educational property, discharging a firearm on educational property, possession of a handgun by a minor, going armed to the terror of the public, and possession of marijuana. Gray was charged with possession of a weapon on educational property, discharging a firearm on educational property, going armed to the terror of the public and possession of drug paraphernalia. Gray pleaded not guilty and is expected back in court in February, according to online records. Lathon pleaded not guilty and is expected back in court in January, according to online records.

Saturday, Aug. 31: Mobile, Alabama

Near the end of a football game at Ladd Peebles Stadium, shots were fired and nine people were injured. Police arrested 17-year-old boy for the incident that occurred after the LeFlore and Williamson high school match up. The teen's criminal case is pending grand jury action, a spokeswoman with the Mobile County District Attorney's Office told with ABC News.

Friday, Sept. 6: Pittsburgh, Pennsylvania

With four minutes left in Jeannette High School's football game, Dameian Williams and Greg Harper reportedly got into a verbal altercation outside the stadium. The argument escalated to a point where 48-year-old Williams was allegedly shot in the chest by 40-year-old Harper after Williams allegedly punched him twice. Williams died at the hospital and Harper was charged with homicide and reckless endangerment. Harper is claiming self-defense and has entered a not guilty plea.

Friday, Sept. 6: Bucks County, Pennsylvania

A bullet from a drive-by shooting after a football game at Morrisville High School against St. Andrews High School, grazed a girl sitting in a car in front of the school. The alleged gunman fired three shots into the car and drove off. No arrests were reported.

50% of school shootings occurred on Fridays, according to ABC News' analysis.

Tuesday, Sept. 10: Aiken, South Carolina

During an alleged physical altercation in the parking lot of South Aiken High School, Markael Khail Forrest allegedly fired a single shot, according to the Aiken Standard. Forrest, 22 was arrested on Sept. 16. Forrest pleaded not guilty for weapons and a non-student interfering, disrupting, or disturbing schools charges. Initially three others were arrested, but according to online records those cases are not pending.

Friday, Sept. 13: Newport News, Virginia

After Woodside and Denbigh high schools finished a football game at Todd Stadium, shots were fired and three teenagers, ages 14 and 19, were injured. No arrest were made, but security was beefed up since the shooting.

Saturday, Sept. 14: Fort Worth, Texas

As a youth football game was happening at Eastern Hills High School, parents got into an altercation and shots were fired, according to the Dallas Morning News. A woman was shot in the leg and her 12-year-old daughter was grazed by a bullet.

Friday, Sept. 20: Philadelphia, Pennsylvania

During the second quarter of a football game between Imhotep Institute Charter High School and Mastery Gratz High School at Marcus Memorial Stadium, multiple shots were fired. A 15-year-old was shot in the thigh and a 14-year-old was shot in the foot. Police said multiple shell casings were found but it is unclear if the shooting happened inside or outside of the stadium. The teens were in stable condition. No arrests were made.

Friday, Sept. 27: Richmond, Virginia

As spectators were leaving a football game at De Anza High School against Pinole Valley High School, a fight broke out. When police arrived at the scene, shots were fired and three teenagers were injured. A 17-year-old boy was shot in the back of the head, 16-year-old girl shot in the upper torso and 17-year-old man shot in the leg, according to the Richmond Standard. No arrests were reported. Two of the victims were listed in serious condition at the time. One was treated and released, according to the report from ABC station KGO.

Wednesday, Oct. 2: Atlanta, Georgia

During a softball game between South Atlantic and Washington high schools, a fight broke out with several of the players and adults when one of the adults fired a shot in the air, according to the Atlanta Journal-Constitution. The unnamed adult was arrested and no one was injured.

Tuesday, Oct. 22: Santa Rosa, California

A pair of students had a verbal argument outside of Ridgway High School that escalated to gunfire. A 16-year-old student was shot in the stomach and a 17-year-old student, was charged as a juvenile with attempted murder. The campus, which also houses another high school and a junior college, was locked down for almost three hours. Police said pair have ties with local gangs and said the shooting escalated a weeks-long dispute that included face-to-face confrontations outside the campus, according to the Press Democrat.

Monday, Nov. 11: Baltimore, Maryland

Just before 2 p.m., a 19-year-old student was outside of Reginald F. Lewis High School when a masked gunman approached and shot him in the leg, according to the Baltimore Sun.

Thursday, Nov. 14: Santa Clarita, California

A 16-year-old gunman opened fire inside Saugus High School killing 15-year-old Gracie Anne Muehlberger and 14-year-old Dominic Blackwell. Three others were injured. The shooter -- who was not included in ABC News' analysis -- killed himself.

Friday, Nov. 15: Pleasantville, New Jersey

During a football game between Pleasantville and Camden high schools, shots were fired in the stands, sending the players and spectators running. Micah Tennant, 10, was shot in the neck and died days later. Two others, including a 15-year-old boy were also injured. Alvin Wyatt, the alleged shooter, was charged with murder and attempted murder. Wyatt, 30, has not entered a plea.