Every school district in the Washington region will close for an extended period starting Monday, a serious escalation in officials’ battle against the growing coronavirus outbreak — and a moment without precedent in the history of Washington-region education.

The closures tumbled out rapid-fire over the course of the day Friday. It began with D.C. Mayor Muriel E. Bowser (D), who announced early in the morning that the District’s public schools would close for at least two weeks. The city’s charter campuses also will close.

Hours later, Virginia systems followed suit: Arlington Public Schools and Falls Church City Public Schools posted on social media that they would close for nearly a month, until students returned from spring break on April 14. Within seconds, Alexandria City Public Schools also tweeted that it would shutter until mid-April.

It fell to Virginia Gov. Ralph Northam (D) to put the capstone on the day — announcing in the early afternoon that he was ordering all public schools in Virginia closed for at least two weeks.

“This is a fluid and fast-changing situation,” Northam said. “We are taking this action to keep Virginians as safe and healthy as possible.”

Maryland announced Thursday that it planned to close all public schools, as coronavirus cases in the Washington region continued to mount — to nearly 60 as of Friday evening.

The sudden shuttering of so many schools will bring massive challenges — feeding students who rely on school-provided lunches and breakfasts and ensuring that children in lower-income families, or with less-stable household situations, do not fall behind academically while stuck at home. It also throws hundreds of part-time employees such as substitute teachers into financial limbo, leaving them without a source of income for an uncertain stretch of time.

Above all else, educators must confront one question — how to keep teaching hundreds of thousands of children from afar in what amounts to a weeks-long experiment in virtual education for which no one had time to prepare.

In an online question-and-answer session held the night before the onslaught of closings, Alexandria Health Department Director Stephen Haering argued against shutting schools for that very reason.

“The downside to closing is kids will get educated in such a different way,” Haering said. “And, if that way were a better way, we would be doing it already.”

Sitting alongside Haering, Alexandria City Public Schools Superintendent Gregory C. Hutchings Jr. repeatedly insisted he would not close schools until directed to do so by the city health department. Shutting down, he said, was a decision with immense, unpredictable consequences and should not be taken without significant provocation — and “we do believe that kids need to be in school every day.”

But the rapidly evolving situation with the coronavirus, superintendents and local officials wrote in statements and emails to families Friday, made it unthinkable to do anything other than close. Authorities sought to walk a line, acknowledging the high stakes and historic nature of the moment — and the pandemic — while assuaging parents’ fears.

The closure in Arlington, which serves roughly 28,000 students, comes “in response to growing concerns and anxiety in our community about the coronavirus,” interim superintendent Cintia Johnson wrote in a message to families.

Johnson’s message, like almost every other email and statement from school districts, rang with the promise of plans. Officials vowed they would offer regular updates to families — at least twice a week in Loudoun County, once a day in Alexandria — and promised to send more detailed instructions on how virtual schooling would work. Emails spelling out plans for online classes or meal programs would come that evening, authorities said, or the next day — or just “soon.”

In the District, the already difficult undertaking of remote learning becomes more complicated because many District students lack computers and reliable access to the Internet.

The closures will affect more than 52,000 students in the District’s traditional public school system. Nearly 50,000 charter school students will also be out of their classrooms.

A spring break that was previously scheduled for late April has been rescheduled to begin March 17. Remote learning is scheduled to begin March 23. Students are expected to return to school April 1.

D.C. Public Schools Chancellor Lewis D. Ferebee has said teachers will work to provide learning resources to students offline and online, and the mayor said teachers and staff would report to work Monday so they can make plans for students to continue to learn during the closure. Ferebee said students left school Friday with textbooks and worksheets, and families can pick up additional work in coming days.

Raymond Weeden, executive director of Thurgood Marshall Academy Public Charter School in Southeast Washington, said he is considering purchasing mobile hotspot devices for some students so they can access learning materials online. He is also looking into setting up a larger WiFi network near a public housing development where many of his students live so they can log on and use online materials.

Weeden estimates a third of his students lack reliable Internet and said it is his responsibility to ensure they receive an education during the closure — no matter the cost.

He is hoping to send students home with school Chromebook laptops during the shutdown.

“Our options are to do it or not do it,” Weeden said. “We are morally obligated to do it, and we’ll figure out how to do it.”

In Alexandria, educators on Friday morning distributed hastily assembled “distance learning” packets to 9,000 middle-schoolers.

The eight-page documents include educational activities — for example, measuring a child’s shadow at 10 a.m. and again at 2 p.m. — and arts and crafts projects. They also offer physical exercises such as jumping jacks, walking around the house to identify every source of water or dancing to classical music while learning about famous composers.

The packets, which give students something to do each day, are designed to carry them through roughly two weeks without school. At Hutchings’s request, Alexandria employees worked long hours this week — in some cases pulling all-nighters — to finalize packets by Friday morning.

“It was 24/7,” said Tanja Mayer-Harding, a humanities instructor who helped compile the packets. “We put in as much work as we possibly, possibly could.”

For students in third grade and older, all of whom receive Chromebooks from the school system, the packets will be supplemented with online programming, Mayer-Harding said. School officials have also developed specialized versions of packets for prekindergartners, students with learning disabilities and students with limited grasp of English.

Arlington Public Schools, by contrast, provided few details Friday. In a four-paragraph message, Johnson, the interim superintendent, said officials would evaluate and monitor the coronavirus outbreak daily and provide updates to families in the system. Her statement was co-signed by Peter Noonan, superintendent of Falls Church schools, which serves 2,700 students.

Johnson and Noonan wrote that they would send “additional logistical details of the closure” later in the day.

Fairfax County Public Schools, whose 188,000 students in Northern Virginia make it one of the largest school districts in the nation, was last to join the slew of cancellations. Several hours after Northam made his announcement, school officials wrote in an email to families that the system would remain shuttered from Monday through April 10.

For Mona Hassan, an 18-year-old senior at South Lakes High School in Reston, the closure came far too late. For at least a week, she and her friends had been urging the school system to shut down, convinced they might contract the coronavirus in the hallways, then pass it to more vulnerable parents and relatives. Students at South Lakes were planning to stage a walkout Tuesday in protest of the decision to stay open, Hassan said.

“I can’t believe it took the governor,” she said. “We had to wait for that to be safe.”

Hassan said she is unsure how she will fill the next month off from school but that she’ll likely spend much of it inside doing homework — a commitment that would please Mayor Bowser, who warned against excess leisure time at a news conference Friday afternoon.

“We are very concerned about idleness among our teenagers,” Bowser said, “so we hope our families are thinking about ways to keep our young people engaged.”

For some students, staying inside to learn may be a tough sell.