Mountain communities were besieged Wednesday after the bridge fire exploded, devastating the Wrightwood area and hitting the famed Mountain High ski area.

Homes were on fire in Wrightwood Tuesday night, sending embers across Highway 2 and flames shooting up both sides of the road. Officials did not provide damage estimates.

Fanned by wind and heat, the fire prompted evacuations in a number of mountain towns, cities and resorts along the state route, with towering flames leaping over hills and canyons. Officials have said they are most concerned about Mount Baldy Village and Wrightwood, but evacuation warnings were also issued for the foothills of Upland and San Antonio Heights.

The bridge fire was one of several large blazes burning in Southern California after a severe heat wave. The airport fire raced up the Santa Ana Mountains in Orange County and moved downhill toward Lake Elsinore, prompting evacuations in some areas. Meanwhile, the line fire sent residents of Running Springs, Arrowbear Lake and other communities fleeing.

The mountainous areas have been hit by gusts of wind even as temperatures have dropped over the past day, with forecasters saying the cooling will continue into the weekend.

Officials were in the process of moving resources from smaller fires to these three major fires in Southern California, as well as resources from out of state through the Emergency Management Assistance Compact program, Cal Fire Battalion Chief Todd Hopkins said at a news conference Tuesday.

A man looks at the flames of the airport fire that envelops a hillside behind homes in Trabuco Canyon.

(Gregory Bull/Associated Press)

Fire on bridge

The bridge fire broke out Sunday in the Angeles National Forest. Fire activity increased in the northeast Tuesday, forest officials said.

The fire danger has been raised to “very high” for visitors to the area, including the San Gabriel Mountains National Monument. The fire has prompted mandatory evacuation orders for communities in the area.

Between Tuesday and early Wednesday, the fire expanded from 4,000 hectares to 47,904 hectares, an area that has more than doubled in size.

The area is remote, but the fire danced in and around mountain landmarks and towns. Video from Mountain High showed flames burning through a ski lift area.

The Line fire rages Tuesday evening south of Running Springs, as seen from Highway 330.

(Gina Ferazzi / Los Angeles Times)

Fire at airport

The airport fire started in Trabuco Canyon and spread first up the canyon, away from the foothill neighborhoods such as Robinson Ranch.

It has now grown to 22,376 acres and was 0% contained as of Wednesday morning. The fire started Monday afternoon amid a persistent heat wave that has fanned fires across the region, brought winds that poisoned the air with smoke and ash, and forced schools and businesses to close until conditions improved.

The storm moved east into the Inland Empire and some homes were lost in isolated areas along the Ortega Highway.

According to investigators with the Orange County Fire Authority, the cause of the airport fire was a spark from heavy equipment workers were using to place large boulders on Trabuco Creek Road. The cause was unintentional.

Eight firefighters and two civilians were injured and sent to local hospitals for treatment Monday and Tuesday, Orange County Fire Authority Capt. Sean Doran told The Times. Two of the victims suffered burns.

OCFA did not provide information about the patients’ conditions or the severity of their injuries.

Buildings in Orange County were damaged, but authorities could not confirm the number of buildings damaged Tuesday evening.

Line fire

The Line fire in San Bernardino County started Thursday and had burned 34,659 acres by Wednesday morning with 14% containment. Evacuations were in effect for several communities southwest of the fire in case the wind shifted.

As of Tuesday evening, the disaster assessment team had not reported any structural damage caused by the Line fire. But according to a Times photographer, at least one home on Pine Cone Drive in Running Springs went up in flames. Thick smoke blanketed the street, causing firefighters and bystanders to have difficulty breathing.