Erica Green of the New York Times writes today that the federal government has finally offered directions for schools faced with the global pandemic:

WASHINGTON — The Centers for Disease Control and Prevention advised schools on Friday that closings for at least eight weeks might be the most effective way to contain the coronavirus. The Education Department released school districts from a slew of testing and accountability measures required by federal law.

But schools across the country were far ahead of the Trump administration’s advice. A cascade of public school closings gained speed nationwide on Friday, with the largest school district in California, the Los Angeles Unified School District, announcing it was closing, along with the San Diego Unified School District. They joined other large cities like Washington, Miami and Seattle, and more than a dozen states like Virginia, Ohio, Maryland, Pennsylvania, Oregon, New Mexico and Michigan.

At least 21,000 schools have been closed or are scheduled to close, according to Education Week, affecting at least 15 million students. A majority of closings announced by school districts range from two to six weeks, which the C.D.C. considered “short- to medium-term closures” that would “not impact” the huge wave of infections that are expected in the next few weeks.

Danny Carlson, the associate executive director of policy and advocacy for the National Association of Elementary School Principals, called the timing of the C.D.C. guidance “baffling.”

“Where was this a week ago?” he said.

The C.D.C. conceded that long-term closings could significantly affect academic outcomes for students, economic conditions for struggling families and health conditions for grandparents who care for students.

And while it had data that could help decide when to close schools, the C.D.C. said it did not have data on the right time to reopen them.

On Thursday, the Education Department announced that it would relieve school systems of some of their responsibilities under federal law. It will consider one-year waivers for state-administered tests or requirements that districts test 95 percent of their students. It would also allow waivers for certain measures of a school’s effectiveness ratings, such as chronic absenteeism, as required under the Every Student Succeeds Act.

The department also said schools were not obligated to provide special education while classes were canceled for all students, but they must resume services when they reopen or if they shift classes online.