Families wait in line to receive free school uniforms and other necessities in the aftermath of Hurricane Harvey on Friday, Sept. 8, 2017, at the Denver Harbor Multi-Service Center in Houston. People waited for hours before the distribution began in lines that stretched around the building. (AP Photo/Matt Rourke)

HOUSTON — Tens of thousands of children are returning to school Monday in Houston, two weeks after Hurricane Harvey battered the city, flooding homes, sweeping away uniforms and school supplies, and shuttering one of the nation’s largest school districts.

The storm, which left 70 percent of Harris County under water, damaged nearly all school buildings in the Houston Independent School District, which educates 216,000 students. More than 200 of the district’s 306 schools were expected to reopen Monday after an aggressive, round-the-clock clean-up effort, while some students will return to school next week or the week after.

The reopening of the school district represents an important step toward normalcy for the city, where many people — including children — are still unable to return home or to work. The district was still trying to get a handle on how many of its students were left homeless by the storm, with many families now holed up with relatives or in motels, or languishing in the sprawling halls of the George R. Brown Convention Center.

As the sun rose Monday, Ruth Rojas walked her two children, 9-year-old Adrian and 11-year-old Joseline, out of the convention center, the place they called home for the last two weeks, since a Coast Guard boat rescued them from their home.

The siblings had attended school in a suburban district, but Ruth was unsure when — or if — they would ever be able to return home. So with the help of school staff stationed inside the sprawling shelter, she registered them at two local schools: Red Elementary and Meyerland Middle.

“I want them to keep up with everything,” said Rojas, who was a caregiver but worries her extended absence means she won’t be able to keep her job. “It was important for me and for them.”

She said her children were eager to get back to school, and with smiles and new backpacks, they boarded a yellow school bus that pulled up outside of the convention center. Rojas said her daughter — who wore donated clothes — worried about not fitting in because she didn’t have a school uniform. The district is relaxing uniform policies, aware that many families are displaced or may have lost them in the flood.

But she was so eager to get back to school that she arose at 5 a.m., worried she would be late.

“They were just excited to know they were going back to school,” Rojas said. “That’s going to get their mind off of everything that’s happening.”

The school system is bracing to welcome back students who may be traumatized or find it difficult to focus when their lives have been upended. All of the district’s staff will receive training in order to help children.

“We know that thousands of students and their families lost everything and are also working hard to figure out what’s next,” said Superintendent Richard A. Carranza during a news conference last week. “The Houston Independent School District, though, feels that we want to get back to the business of schooling our children and having safe environments for our children to come to every single day.”

“We know that many of our students have witnessed trauma . . . by the sheer nature of the catastrophe that happened with Hurricane Harvey,” Carranza said.