MOLALLA, Ore. — Ralph Mitchell’s neighbors were fleeing. Ash rained from the sky. And outside Mr. Mitchell’s natural-medicine business, a police cruiser announced on loudspeaker: “This has been declared a life-threatening fire emergency. You need to evacuate the city.”
Mr. Mitchell was having none of it. He was staying.
“There’s already reports that antifa’s in town, going down the streets looting,” he said, echoing widely discredited rumors on Twitter and Facebook that left-wing activists had been systematically setting blazes. “I’m getting texts.”
Every natural disaster has its holdouts. But the political fear-stoking that accompanied a tumultuous summer of racial-justice protests in Oregon has become a volatile new complication in the catastrophic wildfires that pushed closer to Portland on Friday, as authorities try to evacuate hundreds of thousands of people.
Law enforcement officials across the state said they had been swamped with calls about social media misinformation and begged people to “STOP. SPREADING. RUMORS!” In the line of fire, the swirl of rumors actually helped goad some people into defying evacuation orders so they could stay and guard their homes.
As a Level 3 evacuation on Thursday urged people to “leave now,” an eerie stillness fell over Molalla, an old timber town of 9,000 an hour south of Portland, and the holdout residents girded themselves for two threats. One was the very real 125,000-acre Riverside Fire burning just east of town. The other was the imagined invasion of left-wing mobs and arsonists that multiple law-enforcement agencies have sought to refute.
Residents who remained hosed down their roofs and soaked their lawns. They organized go-bags of baby supplies and clothes, just in case. They scouted for unfamiliar cars on the roads.
“I’m protecting my city,” Troy McNeeley said as he stood in front of the 900-square-foot home he shares with his son, his son’s partner and several cats. “If I see people doing crap, I’m going to hurt them.”
On Wednesday, the police in Portland warned protesters about lighting fires — a seemingly innocuous public safety message that was followed by waves of rumor about arsonists and mayhem. Sheriff’s offices and fire departments already coping with wildfires that have consumed 900,000 acres were flooded with phone calls.
“We are inundated with questions about things that are FAKE stories,” the Jackson County Sheriff’s Office in Medford posted on Facebook. “One example is a story circulating that varies about what group is involved as to setting fires and arrests being made. THIS IS NOT TRUE!”
The F.B.I. said it had also investigated reports that extremists had set wildfires in Oregon “and found them to be untrue.”
Law enforcement agencies in southern Oregon announced on Thursday that they had begun to investigate whether the Almeda Fire had been deliberately set. The fire has burned hundreds of homes around Medford and is tied to two deaths. But the police chief of Ashland told The Oregonian that there was no evidence pointing to anti-fascist activists.
In Molalla, news began to spread through large and active Facebook groups that serve as a town square and local newspaper — a place to share local information, requests for help and, in some cases, unconfirmed gossip.
As conversations churned away online, neighbors called and stopped by each other’s houses and businesses to trade new, unfounded reports: People setting fire to hay bales. A shootout that erupted after a landowner caught someone throwing a Molotov cocktail. (The Clackamas County Sheriff told The Associated Press there was no such report.)
There have been some verified reports of looting and arson, although the authorities have not pointed to any political connections. On Thursday, the Marion County Sheriff’s Office said two men were arrested on charges of attempted theft and burglary after one of them was spotted trying to break into a home in an area burned by the Beachie Fire east of Salem. In Washington State, authorities reported arresting a person on Wednesday who was reportedly setting fire to a median in Puyallup, Wash.
Officials in Clackamas County, which includes Molalla, announced an overnight curfew on Thursday, and Sheriff Craig Roberts said he was stepping up patrols in evacuated areas and urged people to leave.
“We understand people’s concerns about possible increased criminal activity in evacuated areas,” Sheriff Roberts said in a news release.
Some of the misinformation that seeped like smoke across Molalla appears to have begun when two independent videographers, Gabriel Trumbly and his partner, Jennifer Paulsen, arrived outside town at about 9 p.m. on Wednesday to capture images of the immense wildfires.
They put on press vests and gas masks that they have used while shooting video of recent protests in Portland, then walked along the rural road near where Ms. Paulsen had grown up. Mr. Trumbly said one resident was out spraying down property with water and another offered them something to drink.
They got some footage and photos of the flames before deciding to turn back, concerned about the size of the fire and the possibility that power lines could fall in the winds.
But as they returned into cellphone range, Ms. Paulsen went on to Facebook and Twitter looking for fire updates and came across a social media post that was clearly about them, describing their gas masks and vests and suggesting they had gone up the road to start a fire. The person reported trying to follow their Volkswagen sedan.
One person replied: “Are you kidding me shoot em.”
Mr. Trumbly said he pulled off to the side of the road and called the police to explain what he was seeing on social media and what they had been doing south of town. He offered to show the footage of what he captured. The couple was afraid that armed vigilantes might pursue them.
“They think I just burned their houses down and they have guns, and they are angry, and they are scared,” Mr. Trumbly said.
With the fire continuing to advance, the holdouts were posing increasing problems for firefighters, who had to fall back themselves on Thursday to an elementary school four miles outside the evacuation zone in Molalla.
“We still have a bunch of people that haven’t evacuated,” Todd Gary, a division chief of the Molalla Fire Department, said as he leaned against a table in an elementary school classroom four miles north of the evacuation zone. If the wildfire surged into downtown Molalla, Chief Gary knew that his firefighters would have to risk their lives to rescue the holdouts.
“Some of them, you can talk into leaving,” he said. “Others are saying, ‘We can fight this.’ That’s a scary thing.”
In Molalla on Thursday afternoon, firefighters had already gone door to door urging people to evacuate. Passing police officers blared their warnings and shared ominous updates about how quickly the wildfires could explode if the winds revved up and the weather turned.
Chuck McClaugherty said he and about a dozen neighbors had decided to stay to protect their homes from “crowds of looters out of Portland.” He listened to his police scanner as he stockpiled water and wet down his neighbors’ homes as a last line of defense.
“We’re staying put and watching for people who aren’t supposed to be here,” he said.
Patrick McDermott, 36, hitched up a trailer carrying his four-wheelers as his fiancée packed bags of clothing for their family and draped a surgical mask across their 17-month-old daughter’s face. Mr. McDermott was unnerved by what he called a “generational” outbreak of fires that have swallowed entire towns in Washington and Oregon.
But he said he and his fiancée had been watching reports of hooligans in black masks and hoodies pop up on local Facebook groups, and he worried that he was putting his home at risk if he left. He would go, he said, only when the town caught fire.
“You see what they’re doing downtown,” he said, referring to Portland. “It’s going to be a free-for-all. If I’m here and my buddies are here, that’s going to get stopped. This is what we’ve worked for our whole life. We’re not going to let anyone take it.”
Jack Healy reported from Molalla, and Mike Baker from Seattle.