DURHAM, Calif. — On a chilly morning, with a thick fog enshrouding the town, about 40 fifth-graders crammed into a portable classroom in the shadow of Durham’s football stadium and used yellow sticky notes to describe how they felt. “Tierde, sleepy!” “Like nothing.” “Sick & cold, otherwise joyful.”

The exercise has been part of their routine since returning to classes Dec. 3 on a campus that sits a winding, 30-minute drive down the hill from their old school, Ponderosa Elementary, in Paradise, Calif. The fire that swept this swath of Northern California incinerated some of the classrooms at Ponderosa beyond recognition, leaving only the metal skeletons of tiny chairs arranged in rows and circles. It claimed the homes of every child in the fifth-grade class.

The fire that devastated Paradise has left all but two of the small school system’s buildings shuttered. Almost half of the town’s 3,400 students have left, many pushed into far-flung communities — or even other states — by an overwhelmed housing market.

The calamity delivered unprecedented challenges for the town and the school system, and raised questions no one can seem to answer. How do you rebuild and reopen schools when your town has been leveled? Where do the children go in the meantime? When is it safe to allow them back in a community that fire turned into poisonous dust? How do you educate classrooms full of homeless students, many harboring memories of struggling to breathe as they were evacuated on school buses?

And what if it happens again?

“This is a huge new ballgame,” said Jeffrey M. Vincent, deputy director of the Center for Cities and Schools at the University of California at Berkeley. “We’ll be learning a lot from it, and we’ll be looking to improve upon it if — God forbid — we have another one of these.”

The Camp Fire — an inferno of historic dimensions — eclipsed a record of destruction set just a year earlier. Last school year, during a fire season that ravaged California’s wine country and burned swaths of suburban Southern California, the number of schools that reported closing for wildfires jumped tenfold, to more than 1,500. State officials expect that figure to be even higher this academic year, as schools up to 90 miles away from November’s fire were forced to shut down as smoke clogged the air.

Steven D. Herrington, superintendent of Sonoma County schools, said schools in vulnerable counties should consider preparing for fast-moving wildfires by practicing mass evacuations. In his county, the Tubbs Fire in 2017 gutted at least a half-dozen schools.

“We practice for an active shooter,” Herrington said. “But a catastrophic fire that is moving at one football field a minute? You have to think very fast on your feet.”

Keeping a community intact

In the month after the fire, Michelle John, the superintendent in Paradise, and other school officials scrambled to answer the most immediate question: Where would Paradise students go while the district rebuilt?

If they could not rebuild the homes of students, if they could not erase the memories of frightful escapes, school officials could at least attempt to re-create school as it had been. That is why they were insistent that teachers and their students remain together. It was a remarkable feat of logistics at a time when it might have been easier to have children temporarily enroll in other schools.

“The number one thing parents told me is, ‘I want to get my child with their teacher,’ ” John said.

That’s how the principal of Ponderosa, Ed Gregorio, ended up moving his improvised office — really just a card table with a laptop — to a hallway in another school lined with student art. Durham Elementary teachers hurriedly cleaned out and consolidated classrooms to make room for their guests. They made banners to welcome Ponderosa students, including one that reflected their shared mascot: the tiger.

The resumption of school in December brought emotional reunions for students and teachers, some of whom made their escapes from Paradise on a bus filling with smoke, teachers tearing up shirts to give students makeshift breathing masks.

“The best thing, which is kind of the saddest thing, too, is they’re all in the same situations. All of them lost their homes,” said fifth-grade teacher Tracy Leonard, whose home was consumed by the fire and who shared an RV in the weeks after with her husband, three children and several pets, including a rat that evacuated with them.

In the second week of December, Gregorio strolled the campus with his Durham Elementary counterpart, Shirley Williams, admiring an orderly line of Ponderosa kindergartners. Ponderosa had several kindergarten classes consolidated in one classroom at Durham Elementary — packed with as many as 70 5-year-olds.

Gregorio has been the principal of Ponderosa for only a year but knows nearly every student by name.

A girl in line called out: “Mr. G!” As he looked down at her, she folded her hands into the shape of a heart and smiled. Another girl stepped out of line and wrapped her tiny arms around Gregorio’s left leg, seeking a hug. At a time when many students were living in unfamiliar places — the homes of relatives and friends, shelters and even tents pitched near a Walmart — Gregorio afforded a sense of stability.

Even before the fire, educators in Butte County knew many students came to school with trauma brought about by poverty, homelessness or a drug-addicted or incarcerated parent. A 2013 survey of California adults found that three-quarters of Butte County residents reported having lived through a traumatic event as a child, the highest rate in the state.

And now the fire.

Standing in the bustling cafeteria at Durham Elementary one morning, Melissa Ward, the grandmother of first-grader Jazelle Ward, said the girl had been consumed by worry. She had lived with her mother in Paradise, and now three generations of her family were staying at a family friend’s house.

“At first, she was fine, but since she’s been back at school, she’s suddenly afraid of everything,” Ward said. On their drive to school that morning, when a thick fog flowed eerily down hillsides and through the orchards, Jazelle grew afraid, even though morning fog is typical in this region. “She thinks it’s smoke.”

When Jazelle and Ward moved into the friend’s brick home, Jazelle quizzed her grandmother about what the home was made of. “Does it burn?” she asked.

One day in early December, when the midday sun had burned off the fog, teenagers Jasmine and Jade Ryan slipped white paper jumpsuits over their clothes and began raking through what was left of their home — three stories and several years of memories compressed into dust and ash. The sisters felt lucky that their school — an arts-focused charter high school in Chico — was out of the path of the fire. But then their parents, unable to purchase a home nearby, settled in Beaufort, S.C., closer to family. The girls, who had lost all of their possessions, save the clothes they wore and the books they carried on the day of the fire, could not bear to leave their school. So they moved into a single bedroom in the home of their pastor’s son and resumed classes in December.

“In some sense, we’re really lucky,” said Jade, a 16-year-old junior. “We didn’t lose our school community.”

The girls stepped gingerly through the wreckage amid the din of chain saws and cracking tree branches as utility workers pulled down damaged trees. Out of the rubble, the girls pulled teapots and teacups — collected from the years they lived in Shenzhen, China. Gone were Jade’s massive collection of Pink Floyd posters and the equipment that made up the family’s coffee business: a roaster that once sat in the garage and a food truck the family used to peddle coffee beans and drinks.

Jasmine, a 17-year-old senior who stepped through the wreckage in Converse sneakers, reached for a blue ceramic pot near the rear of the house. It cracked and crumbled in her grip.

A volunteer asked Jade how she was faring. “Kinda numb,” she replied, lethargically.

The same real estate forces that pushed the Ryan family out of Butte County are putting a squeeze on Paradise schools. More than a month after the fire, the school system had been unable to find suitable buildings to house the intermediate and high schools in nearby communities — with much of the available real estate snatched up by businesses that went up in flames. Instead, the school system moved all classes for the two schools online and opened drop-in centers where students can get help from teachers.

Some of the only vacant space available on short notice was in a wing in the Chico Mall — wedged between J.C. Penney and Dick’s Sporting Goods, where holiday music serenaded the corridors nonstop. Teachers attempted to make the best of it, dressing mannequins in Paradise High gear and placing them in the storefront.

But for many students, it was a poor substitute for being in school. Cameron Knaus, an 11-year-old sixth-grader who dreams of being a biogeneticist, said she craves her old routine and wishes she could get more homework. She spends long hours at the Chico Mall because there’s no Internet in the trailer where she and her grandmother now live.

“It isn’t as challenging . . . but they are doing the best they can,” Cameron said.

Other students stayed away because the sight of their high school reduced to a storefront in a tired shopping center was too depressing.

By January, the high school had relocated to an office building near Chico Municipal Airport. The intermediate school had settled into a 40,000-square-foot building that once housed an Orchard Supply Hardware store.

As educators grapple with the day-to-day struggles of running a school district hollowed out by fire — buying classroom projectors, connecting frightened students with counselors, trying to find out where thousands of students had scattered — a larger question loomed, one the entire community confronted: What would Paradise look like?

Schools were an essential part of the town — the second-largest employer and the gathering place on Friday nights in the fall when the Paradise Tigers took to the football field. Some schools are salvageable but sit in the middle of vast debris fields devoid of residents. Others burned to the ground.

“I just really believe that everything is going to get back to normal,” said Cameron, the 11-year-old. In a class assignment, she envisioned a new version of her school that included an orchard, a glass-walled classroom and a “slime room” for stress relief. “I don’t want to have a fire stop me from staying where I want to be.”

Angela Fritz contributed to this report.