Loudoun County Public Schools announced Thursday that it will move completely to distance learning starting Tuesday, Dec. 15, in response to rising coronavirus numbers.

The decision to close came after two key coronavirus metrics surpassed the previously decided thresholds for a return to distance learning: the number of new cases per 100,000 persons, and the percentage of coronavirus tests that come back positive.

In November, the Loudoun County School Board decided that schools would automatically revert to distance learning if the test positivity rate surpassed 10% and the total number of new cases per 100,000 people surpassed 200 for five days straight. As of Thursday, the test positivity rate in the county is 10.4%, and the total number of new cases per 100,000 people in the county over the last two weeks has risen to 394, according to data on the Loudoun County Public Schools website. Also, because the Virginia Department of Health retroactively updated data from earlier in the month, the school system learned that the numbers have actually been above the school board’s thresholds since Dec. 6.

“Given this new information, and the expectation that metrics will stay above the thresholds for the foreseeable future, LCPS will revert to 100% distance learning for all students beginning Tuesday, December 15,” wrote superintendent Eric Williams in an email to staff and families on Thursday.

“We understand that this process is disruptive for families of students who have been participating in hybrid in-person learning this fall,” wrote superintendent Eric Williams. “The safety and well-being of all students, staff members, their families and the community continues to be our highest priority, and this decision is being made consistent with our commitment to achieving that objective.”

In-person schooling started up again Loudoun County in October. Pre-Kindergarteners, English-language learners and students with disabilities were among the first to return to classrooms, followed by students in kindergarten, first and second grade. Families who chose not to send their students back to classrooms could continue with virtual learning.

Starting on Dec. 1, the county expanded its hybrid learning model to elementary school students in grades three through five, seniors who attended the Academy of Engineering and Technology, and seniors who attended the Academy of Science. For students whose parents elected to participate, that meant returning to the classroom two days a week.

According to Loudoun County Public Schools, 166 staff and 94 students have tested positive for the coronavirus since schools began tracking the data on Sept. 8.