The bomb threat was just a hoax, but officials at Hebron High School near Dallas took no chances: School officials called the police and locked down the school this week.
Nearly 2,000 miles away, a middle school in Washington state went on lockdown after a student brought a toy gun to class.
But the threat and the gun were real at Berrendo Middle School in Roswell, N.M., where a seventh-grader with a sawed-off shotgun walked into the gymnasium and opened fire on his classmates Tuesday, wounding two of them. School officials and teachers, who had long prepared for such a moment, locked down the school as police officers and parents rushed to the scene.
For students across the country, lockdowns have become a fixture of the school day, the duck-and-cover drills for a generation growing up in the shadow of Columbine High School in Colorado and Sandy Hook Elementary School in Connecticut.
Kindergartners learn to hide quietly behind bookshelves. Teachers warn high school students that the glow of their cellphones could make them targets. Parents get regular text messages from school officials alerting them to lockdowns.
Administrators across the country have worked with police departments in recent years to create detailed plans to secure their schools, an effort that was redoubled after the December 2012 massacre in Newtown, Conn.
At the whiff of a threat, teachers are now instructed to snap off the lights, lock their doors and usher their students into corners and closets. School officials call the police. Students huddle in their classrooms for minutes or hours, playing cards and board games, or just waiting until they get the all-clear.
They kept saying, Lock your doors and keep everyone away from the windows, said Rebecca Grossman, a sophomore at Watertown High School outside Boston, where students have been forced to shelter in place three times this school year, a less serious version of a full lockdown.
The lockdowns were more disruptive than scary, Rebecca said. A bullet was discovered in a classroom last month, and she and her classmates had to stay in place for four hours.
She said the litany of false alarms has desensitized students, who have come to see the responses as just an annoyance.
The lockdowns are part of a constellation of new security measures deployed by schools over the past decade, a complement to closed-circuit cameras, doors that lock automatically and police officers in the building. Most states have passed laws requiring schools to devise safety plans, and several states, including Michigan, Kentucky and North Dakota, specifically require lockdown drills.
Some drills are as simple as a principal making an announcement and students sitting quietly in a darkened classroom. At other schools, police officers and school officials act out a shooting, stalking through the halls like gunmen and testing whether doors have been locked.
School officials and security experts say that the lockdowns are a modest and sensible effort to guard against the unthinkable, and that they have helped keep students safe, calm and organized during shootings and emergencies.
Last month, when an 18-year-old student walked into his high school in suburban Denver and fatally shot a classmate in the head, students huddled in their classrooms behind locked doors as police commandos swept the building. They were evacuated classroom by classroom, hands over their heads, onto the snowy playing fields, all according to a plan school officials had put in place.
The staff and students knew how to safely lock down and then evacuate the school, Scott Murphy, the district superintendent, wrote to parents after the shooting at Arapahoe High School, praising what he called a well-coordinated response.
Even without a direct threat, schools will default to a lockdown. A high school in the San Francisco Bay Area locked down last week as the police in the area hunted for a carjacking suspect.
Some parents wonder whether the trend has laid a backdrop of fear and paranoia across their childrens education.
The North Carolina elementary school where Jackson Green, 5, counts to 100 and delights in celebrating classmates birthdays has gone into lockdown twice this school year, once for a drill and once for real, sending Jackson and his classmates to huddle quietly in a hidden corner until their teacher says everything is OK.
On Oct. 11, the school was locked down for part of the morning after a fifth-grader reported seeing an unfamiliar man in the school, who turned out to be a parent. The school, which locks its doors during the day and has security cameras at all of its doors, alerted parents and called police.
It speaks to the psychological conditions of these children, that theyre alert, theyre on the lookout, that this danger is always present for them, Jacksons mother, Sarah Green, said in an interview. Its constantly on their minds.