EMERALD BAY, Calif. — Crews worked through the night to contain a brush fire that has scorched about 150 acres in the hills above the exclusive Emerald Bay community in Laguna Beach Thursday, threatening but not damaging any of the multimillion-dollar homes in the area, but prompting evacuation orders and forcing schools to close.

As of Friday morning, the fire had burned 145.2 acres and was at 20% containment. Currently, crews are on the line mopping up and patrolling the area, according to the Orange County Fire Authority.

The fire was reported at about 4:10 a.m. and spread quickly throughout the hillside area behind the upscale gated community.

As of 3 p.m., evacuation orders for the communities of north Laguna Beach, Emerald Bay North and South and Irvine Cove were lifted. But county and state parks in the fire-affected areas remain closed.

Evacuation centers were established at the Los Olivos Community Center, 101 Alfonso, Irvine, and Laguna Beach Community Center, 380 Third St.

Pacific Coast Highway was closed between Broadway in Laguna Beach and Newport Coast Drive in Newport Beach.

Orange County Fire Authority Chief Brian Fennessy said at a 7:30 a.m. briefing Thursday the fire had only scorched about 7 to 10 acres. But by 9 a.m., improved mapping showed that the fire had actually scorched 145 acres. As of 3 p.m., the acreage was updated to 150 acres and containment improved from 5% to 10%, according to Orange County Fire Authority Capt. Steve Concialdi said.

At the height of the fire there were 375 firefighters, but by 3 p.m. that number was down to about 200, Concialdi said. Five helicopters have had a “significant impact” on the fire.

“They made significant drops to slow the fire down, and then the wind died down this morning, which helped tremendously,” Concialdi said around midday.

The National Weather Service expected overnight winds to pick up again about 10 p.m.

“We might have some strong gusts this evening,” but firefighters expect to make more headway by then and the agency’s bulldozers have created a “significant firebreak,” Concialdi said.

He noted that there is more moisture in the vegetation because of the season.

The flames erupted amid Santa Ana winds that prompted a wind advisory in the area. The flames were driven primarily by the winds and mountain terrain. The hillsides are filled with thick, dry brush, since the area has not had a significant fire since 1993. Fennessy gave credit to residents for protecting their homes by clearing brush from their properties to create a defensible space.

“Their work in creating defensible space, allowing us ... to have a better opportunity to protect your homes was evident,” he said. “While the fire did spread rapidly, when it got into those areas where there was good defensible space, that fire laid down as it should, and again we had no structure damage and no structure loss,” the chief said.

Along with the OCFA, personnel from the Laguna Beach Fire Department also responded, along with crews in water-dropping helicopters in a mutual-aid response from the Los Angeles County Fire Department and Cal Fire.

Fennessy said there were 75 engine crews fighting the fire, assisted by crews in four Cal Fire air tankers, five hand crews, two bulldozers and five water-dropping helicopters.

Also, law enforcement personnel, including those from the Orange County Sheriff’s Department and the California Highway Patrol, were deployed to secure the area, Fennessy said.

“We’ve got almost an engine in front of every home — that’s how robust the response was,” Fennessy said. “It was really the north end of Emerald Bay ... an unincorporated area of Orange County. So, the fire literally was pushed north along the edges of those homes on the northern edge, and so they were not directly impacted.”

Winds were expected to die down Thursday afternoon, but firefighters were closely monitoring the winds because “they can pick right up again,” Fennessy said.

“And so, our biggest concern would be that fire moving north, jumping where we’ve got it held right now, and moving north towards Newport Beach,” Fennessy said. “I’m satisfied with the number of resources we have at scene, and we have en route; and at this time, I’m feeling pretty confident we’ve got a pretty good handle on this fire right now. ... The bulk of the fire is away from the structures now.”

The massive hillside fire forced the cancellation of classes at all schools in the Laguna Beach Unified School District — El Morro Elementary School, Top of the World Elementary, Thurston Middle School and Laguna Beach High School.

The cause of the fire was under investigation, Fennessy said.