A Los Angeles County wildfire exploded to more than 7,500 acres Friday morning and destroyed dozens of homes.

The Saddleridge Fire, near Sylmar, had been listed at 1,600 acres as of 2 a.m. — but two hours later it was more than twice that, and at 8 a.m. it was more than 4,700 acres, the Los Angeles Fire Department said.

At 1 p.m., 7,542 acres (11.8 square miles) had burned, and containment was at 13 percent, the fire department said. No new perimeter map was released for the expanded acreage.

On the map above, the mandatory evacuation zone is shown in orange tone and the approximate perimeter from Friday morning in the heavy red line. Closed highways are marked in black.

About 23,000 homes were under mandatory evacuation order, most in the Porter Ranch and Oakridge Estates neighborhoods at the north end of the San Fernando Valley.

Twenty-five structures were burned by daybreak, the department’s Friday morning report said. A resident in the fire area suffered cardiac arrest and died at a hospital, and a firefighter suffered a minor eye injury.

The fire broke out after 9 p.m. Thursday northeast of the interchange of interstates 5 and 210. As winds gusted up to 50 mph, the flames crossed both freeways.

I-5 was closed between Calgrove in Santa Clarita and Highway 118. I-210 was closed between Yarnell Avenue in Sylmar and Highway 118. Stretches of I-405 and highways 14 and 118 were also closed.

The Saddleridge Fire is 13 miles northeast of the November 2018 Woolsey Fire, which burned 96,949 acres and destroyed 1,643 buildings.

Four other wildland fires also broke out Thursday in Southern California: the Wendy Fire, near the Ventura County coast, and a trio of fires (Wolf, Reche, Sandalwood) in western Riverside County.

On Yosemite’s western edge, the 5-day-old Briceburg Fire was holding steady around 4,900 acres, with 30 percent containment, CalFire said. Thirteen miles of Highway 140 remained closed north of the town of Mariposa.