Glendora - Santa Ana winds that fanned a campfire into a wildfire that destroyed five homes and threatened foothill neighbourhoods east of Los Angeles relented on Thursday afternoon, halting the blaze in its tracks.
The fire swept through 1 700 acres of brush in the San Gabriel Mountains early in the day and drove some 3 700 people to evacuate, but by nightfall it was no longer advancing and was 30% contained.
"The weather co-operated quite a bit today. We didn't get the wind that we thought", Los Angeles county fire deputy chief John Tripp said.
The contained sections of the fire were those closest to populated areas, allowing residents to return to neighbourhoods in Glendora on Thursday night, though fire engines would remain.
Parts of neighbouring Azusa remained under evacuation orders. It wasn't clear how many of the evacuees remained away from their homes.
The national weather service said a red-flag warning of extreme fire danger would remain in effect into Friday evening because of low humidity and the chance of winds gusting to 50km/h in the foothills and canyons.
The wildfire, which erupted early on Thursday, damaged 17 homes, garages, barns and other buildings, Tripp said.
Visibility from space
At least 10 renters were left homeless when the fire destroyed rental units on the historic grounds of a retreat that once was the summer estate of the Singer sewing machine family. Statues of Jesus and Mary stood unharmed near the blackened ruins. However, the main, 1920s mansion was spared.
Two fire-fighters had minor injuries and a woman trying to fight the blaze near her home suffered a minor burn, Tripp said.
Three men in their 20s, including a homeless man, were arrested on suspicion of recklessly starting the blaze by tossing paper into a campfire in the Angeles National Forest, just north of Glendora.
Glendora chief Tim Staab said the men were trying to keep warm and the wildfire appears to have been an accident.
More than 700 fire-fighters were on the scene, along with 70 engines and a fleet of helicopters and air tankers dropping water and retardant.
The smoke was visible from space in satellite photos. The South Coast Air Quality Management District issued a smoke advisory and urged residents to avoid unnecessary outdoor activities in directly affected areas.
Large parts of Southern California have been buffeted all week by the region's notorious Santa Ana winds, which have contributed to some of the region's worst wildfires.