Marco Cavalletti has spent months organizing large orders of KN95 masks — including kid-sized ones — for his family and others in Minneapolis who are trying to protect themselves against COVID-19. But this week, amid the omicron variant surge, he noticed more urgency and anxiety in the messages he received from fellow parents.

"People are desperate and looking for something tangible they can do because everything is overwhelming right now," Cavalletti said.

Schools are overwhelmed, too. In the few days back after winter break, omicron's rapid spread has already proved disruptive. By Friday, many classrooms were half full because so many students were out sick or in quarantine. And districts were scrambling to cobble together solutions to cover for staff absences that, in some cases, surpassed 25%.

In St. Paul, only about half of classrooms that needed substitutes were able to get them. Some Minneapolis high schools were down so many teachers and subs, they moved several unattended classes to lunchrooms or other common areas, where students worked online.

Other districts, including Robbinsdale and St. Anthony-New Brighton, switched entire schools to online learning for a few weeks. On Friday, the Worthington school district canceled all classes through next Tuesday because of "increasing illness numbers in both students and staff." Several districts, including St. Paul, also sent parents notes warning of major transportation delays or cancellations because of bus driver shortages.

Still, school leaders across Minnesota say they are committed to in-person learning and are implementing a variety of solutions to cover staffing needs.

"It's like every aspect of our organization is at its breaking point, and we're all pulling together to hold on," said David Law, superintendent of the Anoka-Hennepin school district.

Staffing and substitute shortages were already overstretching educators and rising COVID-19 case counts have only exacerbated the problem, state education leaders say. And the problem isn't limited to public schools: Principals in all corners of Minnesota are spending their mornings figuring out how to move teachers and other staff around to cover for those who are absent. Many districts, including Minneapolis, St. Paul and Anoka-Hennepin, are also pulling staff from central district offices to help fill in gaps.

"A local store can decide to close early when they're short staffed," Law said. "We know when we're short staffed, we can't just turn off the lights, close up and say, 'We'll try again tomorrow.'"

Still, a temporary period of distance learning may help some schools survive the worst of the latest peak in infections, said Denise Specht, president of Education Minnesota, the state teachers union. That's not the right decision for all schools, but it may help relieve some pressure, she said.

"All educators want to be working directly with students ... we want to be able to do that for as long as possible," Specht said. But, she added, the current conditions are "very challenging and not sustainable."

Greta Callahan, president of the Minneapolis teachers union, has been collecting lists of teacher absences this week. "It's more than ever," she said.

Students are also staying home or being sent home in droves — often with at-home test kits in hand, said Kelly Woods, principal of Bethune Elementary in Minneapolis.

"Every day, we have positive cases," Woods said. She's hearing from parents who can't take time off from their jobs to stay home with their children, as well as those who are afraid to send their kids to school.

The Minneapolis teachers union this week again renewed its call for the district to make a plan to offer school-specific online options for students to continue learning at home. The district's online school, which requires families to unenroll from in-person learning, has a waitlist.

"We need to go to distance learning for two weeks to get over the surge," Callahan said. "And when our students come back, they need a robust plan in place to reach those in quarantine."

Both the Minneapolis and St. Paul school districts are in mediation with their teachers unions.

Amy Hewett-Olatunde, who teaches English as a second language at St. Paul's Humboldt High School, said it was hard to continue her lessons this week when a third of her class was absent. And when those students return to class, it's likely that another chunk will be at home.

"Of course we want to teach them in person, but they are dropping like flies," she said.

Hewett-Olatunde's students and their families are confused about how safe their school is and her colleagues feel guilty when they call in sick, she said.

"There's just this overall feeling of instability," she said. "It's like we're at a tipping point and everybody is waiting for that implosion."

Joe Gothard, superintendent of St. Paul Public Schools, said a move to remote learning presents its own challenges, including getting devices, internet service and meals to students.

"I hate to say that we're either all in or all out," he said, "but anything in between [in-person and distance learning] is a stress on a system already at a breaking point," he said.

Amy Kujawski, principal of St. Anthony Middle School in St. Anthony, said she spent her winter break bracing for more staff to be out sick. By Tuesday, more than 10% of her teachers were at home. That helped trigger the decision to move the district's schools into online learning for the rest of the month, although students can still come into the buildings to work.

"I can't stretch my already limited staff enough to make a typical day work, and that's devastating," Kujawski said. "Coming back in September was like the brightest rainbow after the worst, darkest storm. And now to be in a place where we're asking students to stay home again feels really awful. But we don't have an option."

Despite the high number of student and staff absences in Anoka-Hennepin schools, Law said most students are still getting in-person instruction.

"If we can hold onto that, we won't compound [learning loss]," he said. "We are doing everything we can to keep our kids in school. There is no enemy here but the pandemic."