Cal Fire air tankers help stop the spread of a brush fire in Larkfield Calif, on Thursday. Kent Porter/The Press Democrat via AP

SAN FRANCISCO — Firefighters and officials at California’s largest utility company braced for hot, dry and windy weather in northern and central areas of the state this weekend that may fan the flames of several major wildfires or ignite new ones.

Pacific Gas & Electric warned Friday it may cut power from Sunday morning to Monday, potentially affecting 97,000 customers in 16 counties, during which forecasters said a ridge of high pressure will raise temperatures and generate gusts flowing from the interior to the coast.

PG&E initially warned that approximately 21,000 customers in three counties would lose power beginning Saturday evening but expanded the potential shutoff when the forecast changed.

The utility is tracking the weather to determine if it would be necessary to shut off power to areas where gusts could damage the company’s equipment or hurl debris into lines that can ignite flammable vegetation.

When heavy winds were predicted earlier this month, PG&E cut power to about 167,000 homes and businesses in central and Northern California in a more targeted approach after being criticized last year for acting too broadly when it blacked out 2 million customers to prevent fires.

PG&E equipment has sparked past large wildfires, including the 2018 fire that destroyed much of the Sierra foothills town of Paradise and killed 85 people.

Firefighters battling the state’s largest wildfire braced for the change in weather by constructing fuel breaks on Friday to keep the flames from reaching a marijuana-growing enclave where authorities said many of the locals have refused to evacuate and abandon their maturing crops.

The wildfire called the August Complex is nearing the small communities of Post Mountain and Trinity Pines, about 200 miles northwest of Sacramento, the Los Angeles Times reported.

Law enforcement officers went door to door warning of the encroaching fire danger but could not force residents to evacuate, Trinity County Sheriff’s Department Deputy Nate Trujillo said.

“It’s mainly growers,” Trujillo said. “And a lot of them, they don’t want to leave because that is their livelihood.”

As many as 1,000 people remained in Post Mountain and Trinity Pines, authorities and local residents estimated Thursday.

Numerous studies in recent years have linked bigger U.S. wildfires to global warming from the burning of coal, oil and gas, especially because climate change has made California much drier. A drier California means plants are more flammable.

The U.S. Forest Service’s Pacific Southwest Region announced Friday that it is extending the closure of all nine national forests in California due to concerns including fire conditions and critical limitations on firefighting resources.

The threatened marijuana growing area is in the Emerald Triangle, a three-county corner of Northern California that by some estimates is the nation’s largest cannabis-producing region.

People familiar with Trinity Pines said the community has up to 40 legal farms, with more than 10 times that number in hidden, illegal growing areas.

Growers are wary of leaving the plants vulnerable to flames or thieves. Each farm has crops worth half a million dollars or more and many are within days or weeks of harvest.

One estimate put the value of the area’s legal marijuana crop at about $20 million.

“There (are) millions of dollars, millions and millions of dollars of marijuana out there,” Trujillo said. “Some of those plants are 16 feet tall, and they are all in the budding stages of growth right now.”

Gunfire in the region is common. A recent night brought what locals dubbed the “roll call” of cannabis cultivators shooting rounds from pistols and automatic weapons as warnings to outsiders, said Post Mountain volunteer Fire Chief Astrid Dobo, who also manages legal cannabis farms.

Hundreds of migrant workers typically pour into the area this time of year to help trim and harvest the plants, but it’s uncertain whether that population dwindled due to the coronavirus pandemic, said Julia Rubinic, a member of the Trinity County Agriculture Alliance, which represents licensed cannabis growers.

Mike McMillan, spokesman for the federal incident command team managing the northern section of the August Complex, said fire officials plan to deliver a clear message that ”we are not going to die to save people. That is not our job.”

“We are going to knock door to door and tell them once again,” McMillan said. “However, if they choose to stay and if the fire situation becomes, as we say, very dynamic and very dangerous … we are not going to risk our lives.”

A firefighter was killed and another was injured on Aug. 31 while working on the fire. Diana Jones, a volunteer firefighter from Texas, was among 26 people who have died since more than two dozen major wildfires broke out across the state last month.

A memorial service was held Friday for a veteran firefighter, Charles Morton, 39, a squad boss with the Big Bear Interagency Hotshot Crew who died Sept. 17 while battling the El Dorado Fire in the San Bernardino National Forest east of Los Angeles.

“I know that Charlie was a very skilled, in fact extraordinary, firefighter and a fire leader,” U.S. Forest Service Chief Vicki Christiansen told the gathering at The Rock Church in San Bernardino.

“He committed himself, often for weeks and months on end, to protecting lives, communities and natural resources all around this country in service to fellow Americans.”

The Butte County Sheriff’s Office on Friday released the identity of another of the 15 people killed in a rampaging forest fire earlier this month. The remains of Linda Longenbach, 71, of Berry Creek, were found on Sept. 10 in a roadway about 10 feet from an ATV, close to the body of a man previously identified as Paul Winer, 68.

A relative told investigators the victims were aware of the fire and chose not to evacuate.