The city of Los Angeles is on high alert as two uncontained wildfires, spurred on by a heatwave and gusty winds, reach within 30 km of the suburban towns of Duarte and Azusa forcing evacuations in the area.
Hundreds of firefighters battled raging wildfires in the western United States on Tuesday amid a record-setting heat wave that has claimed at least four lives and triggered evacuations.
More than 600 firefighters and water-dropping helicopters worked to contain two major brush fires that erupted east of Los Angeles on Monday, scorching more than 5,400 acres and forcing about 800 families to flee their homes.
There are fears that the two rapidly growing, uncontrolled wildfires could merge and force even more communities to evacuate their homes, authorities said on Tuesday.
In a statement issued by the US Forest Service, the so-called Fish Fire and the Reservoir Fire, which broke out on Monday in the Angeles National Forest, more than doubled in size overnight, raising fears of an impending inferno.
While the two blazes have not yet merged, they are being handled as one incident, called the San Gabriel Complex Fire.
The Fish Fire, whose cause is under investigation, has grown to 3,000 acres while the Reservoir Fire, which fire officials say was sparked by a car crash, stood at about 2,400 acres, according to figures from the US Forest Service.
The wildfires are a few kilometres apart in parched and windy foothills just northeast of Los Angeles.
"It is a possibility that the two fires would merge," Andrew Mitchell, a spokesman for the team battling the Reservoir Fire said.
More than 800 people were forced to evacuate the area when the fires reached a distance of 32 km northeast of downtown Los Angeles, Mitchell said. The communities nearest the flames include the suburban towns of Duarte and Azusa.
Overnight, a flank of the Fish Fire crept down a hillside on the east side of Duarte, lapping at brush just beyond some houses before firefighters extinguished the flames, Los Angeles County Fire Chief John Tripp said at a news conference.
"Our big threat today is still that left side of the fire," Tripp said. "That still is a very uncontrolled flank of the fire."
Officials warned more evacuations could be ordered.
California and other southwestern US states have recently experienced intense heat waves leading to a five-year drought. Temperatures have reached more than 40 degrees celsius making the firefighters' ability to try to contain the fire even more challenging.
The National Weather Service Los Angeles has issued a red flag alert for the mountainous region, warning of the danger that a fire can start at anytime and spread rapidly.
Meanwhile, a half-dozen other wildfires burned across California.
In the coastal part of the state, firefighters have made steady progress in handling the so-called Sherpa Fire, a seven-day old blaze northwest of Santa Barbara that has burned nearly 8,000 acres in an area of ranches and campgrounds. That fire is 70 percent contained, according to tracking website InciWeb.gov.
Two states away, the Dog Head Fire in central New Mexico has charred more than 17,000 acres and was 46 percent contained after destroying 24 homes and 21 minor structures soon after it broke out last week.