A deadly wildfire destroyed dozens of homes as it roared through a tinder-dry Southern California forest, forced thousands of residents to flee and burned dangerously close to a vital mountaintop broadcasting complex.
Fire crews battling the blaze in the Angeles National Forest tried desperately to beat back the flames and prayed for weather conditions to ease.
The fire was the largest of at least eight burning across California after days of triple-digit temperatures and low humidity.
The fire scorched 164 square miles of brush, destroyed 53 homes and threatened more than 12,000 others, but the lack of wind kept them from driving stormily into the hearts of the dense suburbs north east of Los Angeles.
Columns of smoke billowed high into the air before dispersing into a gauzy white haze that burned eyes and prompted warnings of unhealthy air throughout the Los Angeles area. Smoke could be seen billowing around the fabled Hollywood sign.
"It's burning everywhere," US Forest Service spokeswoman Dianne Cahir said. "When it gets into canyons that haven't burned in numerous years, it takes off. If you have any insight into the good Lord upstairs, put in a request."
The exact number of people injured or threatened by the fire was still not clear.
During the weekend, three people who refused to evacuate were burned when they were overrun by flames, including a couple who had sought refuge in a hot tub, authorities said.
Fire crews set backfires and sprayed fire retardant at Mount Wilson, home to at least 20 television transmission towers, radio and mobile phone antennas, and the century-old Mount Wilson Observatory.
The observatory also houses two giant telescopes and several multimillion-dollar university programmes. It is both a landmark for its historic discoveries and a thriving modern centre for astronomy.
If the flames hit the mountain, mobile phone service and TV and radio transmissions would be disrupted, but the extent was unclear.
The blaze killed two firefighters who died when their fire engine drove off the side of a road with flames all around them.
The victims were fire Captain Tedmund Hall, 47, of San Bernardino County, and firefighter Specialist Arnaldo "Arnie" Quinones, 35, of Palmdale. Capt Hall was a 26-year veteran, and Specialist Quinones had been a county firefighter for eight years.
They died fighting a fire that showed no signs of subsiding yesterday. People who fled returned to find their homes gone.
The blaze in the Los Angeles foothills is the biggest, but not most destructive, of California's wildfires. North east of Sacramento, a wind-driven fire destroyed 60 structures over the weekend, many of them homes in the town of Auburn.
The 275-acre blaze was 50% contained late last night and full containment was expected today. It wiped out an entire cul-de-sac, leaving only smouldering ruins, a handful of chimneys and burned cars.
California governor Arnold Schwarzenegger toured the Auburn area, where only charred remnants of homes remained. At some houses, the only things left on the foundation were metal cabinets and washers and dryers.
"It was embers travelling in the wind, landing on the roofs, landing on attics, getting into that home and burning the home on fire," said Daniel Berlant, spokesman for the California Department of Forestry and Fire Protection.
Some mandatory evacuation orders were lifted, but most residents are still being told to stay away while crews work to restore electricity and hose down embers.
East of Los Angeles, a 1,000-acre fire threatened 2,000 homes and forced the evacuation of a scenic community of apple orchards in an oak-studded area of San Bernardino County. Brush in the area had not burned for a century, fire officials said.
With highs topping 100 degrees (38 Celsius) in some areas and humidity remaining low, the National Weather Service extended a weekend warning of extreme fire conditions in the central and Southern California mountains.