Failure rates in math and English jumped as much as sixfold for some of the most vulnerable students in Maryland’s largest school system, according to data released as the pandemic’s toll becomes increasingly visible in schools across the country.

In but one stark example, more than 36 percent of ninth-graders from low-income families failed the first marking period in English. That compares with fewer than 6 percent last year, when the same students took English in eighth grade.

“It breaks my heart to see so many of these numbers,” Rebecca Smondrowski, a school board member, said after the numbers were shared at a board meeting Thursday. “We knew that gaps were going to get bigger, but these are huge.”

The data comes as neighboring Fairfax County in Virginia recently reported a sharp increase in failing grades for its students — one of the first systems nationally to detail the fallout of pandemic-driven online education.

In Montgomery, a diverse system of more than 161,000 students, Black and Hispanic students from families at or near the poverty line were among the most severely affected groups, along with English language learners.

Nearly 45 percent of those with limited English proficiency failed the first marking period in ninth-grade math, for instance — a stunning figure given that only 8 percent of the same students failed math in the first marking period last fall.

The data is a grim and vivid reflection of the struggle many students face with remote instruction. Some find the volume of independent work or screen time overwhelming. Some are trying to manage child-care duties, technology glitches, family difficulties or jobs.

Learning in Montgomery County has been all-virtual since March, when public schools across the nation were shuttered as the coronavirus spread. But officials were more forgiving with grades in spring, saying students should not be penalized for disruptions they did not cause as the school system embarked on an unprecedented experiment with online education.

This fall, with classes still online but with greater preparation, Montgomery returned to its traditional grading system. In recent weeks, it has been considering a plan to reopen school buildings in January, but with coronavirus cases surging that remains an open question.

The new data on grades points to critical questions about how to measure the performance of students who attend school from home. Some learners have the advantage of oversight and support from parents or siblings. In other families, parents work at jobs outside the home, face language barriers or are less familiar with material being taught.

Diego Uriburu, co-founder of the Black and Brown Coalition for Educational Equity and Excellence, an advocacy group in Montgomery County, described the reaction he was hearing as a mix of anger, disappointment and despair.

“We are angry,” he said. “It’s not that they can change things on a dime, but from our communities’ perspective nothing has changed from before the pandemic. We hoped that the pandemic was going to be a wake-up call and an inflection point.”

He emphasized the importance of placing the most effective teachers and principals in schools most affected by poverty. Long-standing learning losses still need to be addressed, he said, along with issues of cultural competency.

“They work very hard, but their efforts are not reaching our communities,” he said. “This is a catastrophe, a huge catastrophe.”

The data Montgomery presented Thursday was limited to students in grades six, nine and 12. It was broken down by race, ethnicity and other characteristics to get at which students were most affected.

Montgomery’s nationally regarded school system was roughly 32 percent Hispanic, 27 percent White, 21 percent Black, 14 percent Asian and 5 percent multiracial in the past school year.

Among sixth-graders taking math, Hispanic students from low-income families fared worst, with last year’s failure rate of 4 percent soaring to nearly 24 percent this fall.

Least affected among the sixth-graders in math was a category that included White and Asian students from families not identified as low-income. Last year, less than 1 percent of that group failed the first marking period, and this year it was slightly more than 1 percent.

In many cases, percentages of A’s and B’s dropped as the share of failing grades increased. In some cases, A’s increased markedly, even as failing grades climbed.

For sixth-grade students in special education taking English, for example, the percentage of A’s shot up from 16 percent last year to 27 percent this fall, even as failing grades doubled, from less than 5 percent to 10 percent.

Overall, students in special education experienced significant spikes in failing grades. In sixth-grade math, fewer than 6 percent of students in special education failed last year — compared with nearly 16 percent this year.

In ninth-grade English, some students in special education who passed last year failed this year; the failure rate jumped from 6 percent to 32 percent.

School officials said they are making changes to grading practices, student supports and instructional guidance — adding flexibility with due dates, for example, and reducing the number of recommended assignments that are graded.

Janet Wilson, chief of teaching, learning and schools, pointed to a learning curve as the district moved into new territory with remote learning. The system is bringing practice more into line with a virtual setting, she said.

“We’ve never done this before,” she said.

Before the school year started, administrators worked with educators, students and parents to create what they thought was strong guidance for the first marking period, said Scott Murphy, director of college and career readiness and districtwide programs.

“What we’ve learned is that for many, many, many students, it was too much — too many assignments, too much work to do, managing it across seven, eight classes,” Murphy said. “We had some grade books for the first marking period that had 20, 30, even more assignments in one class, and the pretty consistent feedback we got was it was too much.”

The issue is directly tied to student anxiety and well-being, he said, and “the stress students have right now, and trying to help them manage the volume of work that they have.”

Cynthia Simonson, president of Montgomery’s countywide council of PTAs, said it has been clear that students are struggling, especially those in special education and English language learners.

“That’s probably a very realistic portrayal of what’s happening,” she said. “I think it means we are teaching the content with the same rigor, and I think it’s incredibly sad. This means we are failing to meet the needs of that many students.”

In another sign of academic slippage amid the pandemic, new data from Arlington Public Schools showed slight overall performance drops — in the single digits — on a literacy assessment for kindergartners, first-graders and second-graders, but much steeper declines for students of color and English learners.

The share of Hispanic students meeting the benchmark dropped nearly 15 points, to 60 percent, while the percentage of Black students hitting the mark dropped by roughly 10 points, to 78 percent. The results for English learners in the first and second grades fell even more precipitously, with drops of 26 to 30 points.