SAN FRANCISCO >> Search teams that rushed to Northern California after fire leveled entire towns have completed their work, having checked every burned building in the fire zone for human remains, the authorities said today.

But the search of nearly 18,000 fire-ravaged structures — everything from homes, churches, stores and garden sheds — has not resolved the question of why nearly 200 people remain on the list of the missing.

It is possible that the death toll, which stands at 88, will rise, if some remains were overlooked or are found later in forests or other areas that were not searched.

Sheriff Kory L. Honea of Butte County, who led the search, said today that he was “very optimistic” that people listed as unaccounted for would be found alive and that the death toll was close to final.

“Given the due diligence that was done with regard to the search for human remains in the affected area, I am very hopeful that we won’t see any kind of increase,” he said.

The fire, which ignited Nov. 8 and destroyed 13,696 homes in and around the town of Paradise, north of Sacramento, is by far the most destructive in California history.

The 10,000 specialists from across California and four other states — Nevada, New Mexico, Oregon and Texas — who assisted in the search for human remains have gone home, Honea said. Any additional searches will be handled by the staff of the Butte County Sheriff’s Office.

The experts who conducted the searches first checked what they called “Priority 1” locations — burned structures where the authorities had information from a firefighter, police officer or another emergency worker that led them to believe that someone had died there.

Once those locations had been scoured, search teams moved to “Priority 2” locations — areas where there was a relatively high probability of finding human remains, like mobile home parks or apartment complexes. Finally, the search teams mapped out and searched every other destroyed structure in the fire zone.

Medical examiners have what they term “positive identifications” in 35 of the 88 dead — 22 remains were identified by DNA; 12 through dental records, four by fingerprints and two through photographs. In addition, 47 remains have been tentatively identified through circumstantial evidence such as the address where the remains were found.

Six of the remains have not yet been identified.

The list of unaccounted-for residents was compiled by the sheriff’s office from 911 calls during the fire and from thousands of calls and emails that the office receive in the weeks afterward. If there was any doubt, officials included a name as a precaution. Then detectives spent more than two weeks whittling down the list by calling relatives or checking social media. That work continues.

One pitfall is that those who are safe have little incentive to check the list and in dozens of cases they have been found unharmed — and unaware that they were listed as missing.

Honea gave the example of a group of people mistakenly on the list, an error that someone on his staff discovered this week.

“My secretary looked at the list and said, ‘I know these people — they live in a trailer in Oroville,’” he said, referring to a city not far from the fire zone. “They didn’t think to look on the list and they didn’t know anybody was looking for them.”

Even in an age of ubiquitous mobile phones and social media accounts, tracking down missing people has proved arduous.

Last year it took months to find the more than 2,200 people unaccounted for in Sonoma County after the fires incinerated thousands of homes. The death toll in Sonoma from that fire was finalized at 24.

The town of Paradise, which had a population of 27,000, has remained evacuated since the fire. But Honea said Wednesday that he would allow residents to return in phases starting early next week. Inclement weather could complicate the repopulation of the area, which was under a flash flood warning today. Officials have feared that heavy rains could trigger mudslides in fire-scarred forests.

The 88 people killed in the Camp Fire, as it is known, make it the deadliest wildfire in the United States in at least a century, according to a list by the federal government’s National Interagency Fire Center.

The most deadly wildfire on record, the Peshtigo fire in Wisconsin, killed about 1,500 people in 1871, according to the Wisconsin Historical Society.