LOS ANGELES — A wind-driven brush fire carved a devastating path in the northern foothills of the San Fernando Valley on Friday, chewing through 7,500 acres, burning at least 25 homes and forcing thousands to flee.

The Saddleridge fire, which broke out about 9 p.m. PDT Thursday on the north side of the 210 Freeway in Sylmar amid strong Santa Ana winds, spread rapidly westward into Porter Ranch and other communities. At its peak, the blaze was moving at a rate of roughly 800 acres per hour.

It was 13% contained as of Friday afternoon, Los Angeles fire officials said.

Mandatory evacuations were issued overnight to roughly 23,000 homes encompassing a large swath of neighborhoods north of the 118 Freeway from Tampa Avenue all the way to the Ventura County line — an area covering 100,000 residents. Officials warned that other communities near the fire need to be ready to leave at a moment’s notice if the winds shift.

“The fact that community members heeded evacuation warnings early made a huge difference, allowing firefighters to enter those communities and protect properties,” said Los Angeles County Fire Chief Deputy David R. Richardson.

Conversely, Los Angeles Police Department Chief Michel Moore said he’s seen homeowners stay behind to battle raging flames on their property with garden hoses. He urged residents to evacuate when ordered.

“Those individuals placed not only themselves in imminent peril, but they placed first responders such as police and fire officials in that same perilous condition because of our need and desire to go in and try to rescue them,” Moore said.

One firefighter suffered a minor injury to his eye while battling the blaze, and a man in his late 50s died after suffering a heart attack while talking with firefighters early Friday, officials said. Authorities could not confirm reports that the man was trying to fight the fire from his home before he was stricken.

More than 1,000 firefighters from multiple agencies continued attacking the blaze from the air and ground and by Friday afternoon conditions appeared to be improving, officials said.

Helicopters and amphibious firefighting aircraft known as Super Scoopers were deployed, while ground crews manned bulldozers to cut containment lines into nearby hillsides in an effort to slow the fire’s spread. At least one air tanker blanketed fire retardant across the ridges between Granada Hills and Porter Ranch.

However, low humidity and northeasterly winds gusting up to 50 mph, which are expected to linger until the evening, still pose a challenge for firefighters. Officials say they expect it will take days to get the blaze under control.

The wind has continued pushing the fire west into residential neighborhoods in Porter Ranch and farther west to less-populated areas approaching Rocky Creek Park near the Ventura County line, said Capt. Branden Silverman, an LAFD spokesman.

Porter Ranch is “basically the hot spot right now,” Silverman said. “We’re trying to keep it boxed in above the 118 Freeway. Obviously that’s a good fire break for us, but if the winds shift to the south, then that would be into Chatsworth.”

Silverman said the blaze is similar to the Sayre fire that burned near Sylmar in 2008 and destroyed nearly 500 homes, including the Oakridge mobile home park, which had to be evacuated Thursday. The Sayre blaze was among the most destructive wildfires in the city’s history.

Overnight, the Saddleridge fire moved so quickly that it jumped into neighborhoods before firefighters and police could warn residents.

In Porter Ranch, a man stared as waves of embers crested against a two-story home abutting a hillside on Sheffield Way and flames lapped at the back of the structure.

“That’s my home,” he said. He had gotten out 15 minutes earlier.

Flames had already reached a second home on the cul-de-sac, which was choked with thick gray smoke, punctured only by the high beams of fleeing cars speeding through the small streets that crisscross the hillsides.

The speed of the wind-whipped inferno took many by surprise.

After her husband went to bed Thursday evening in their Granada Hills home, Patricia Strucke flicked on the 9 o’clock news and saw flames. The 79-year-old retired nurse started to feel sick as she watched the broadcast from Calimesa, thinking of the families some 90 miles away whose homes were at risk.

“Your house can be gone in five minutes,” she remembers thinking. “I can’t watch this. It’s too horrible.”

She walked into the kitchen and put her empty glass in the sink. Then, she looked up. Through her kitchen window, she saw a glowing red semicircle licking at the hills.

“My God!” she said. “There’s a fire in Sylmar.”

She rushed to wake her husband, Edward, 77, who uses a wheelchair, warning him they may need to evacuate. She packed up their medications and threw them into the back of their van, but noticed that the fire seemed a bit smaller.

Officials didn’t come by knocking or blaring, “Evacuate now!” on loudspeakers like they had during past fires in the area, but Patricia kept checking outside. Around 11:30 p.m., as the deep red flames were chewing down a hill about 200 yards from their home, she barged into the couple’s bedroom.

“Get up!” she told her husband. “We’re going.”

Edward slipped on shoes and got into his wheelchair. Outside, ash rained down on the home they’d lived in for 45 years.

As they drove away, Patricia realized she’d forgotten her husband’s most important medication, an anti-coagulate, but it was too late to go back. She thought, too, of the many memories they’d made inside the home now shrinking in the rearview mirror. She thought of her two grandchildren, now teenagers, and how they’d learned to swim in their backyard pool. She thought of the times they came over after school to do homework or when they helped tend her tomato plants. She thought of all the holidays, all the times she’d made fudge in her kitchen.

“Am I going to have a home?” she thought.

Around 8:30 a.m. Friday, a neighbor called to say that