Much of California was on high alert on Friday as wind-driven wildfires tore through the state's south, forcing the evacuation of tens of thousands of people and destroying multiple structures and homes.
News reports said an 89-year-old woman died in Calimesa, about 115km east of Los Angeles, when fire swept through a mobile home park overnight after the driver of a garbage truck that caught fire dumped his burning load nearby.
Another man in his 50s died on Thursday night from cardiac arrest as he spoke with firefighters battling the so-called Saddleridge brush fire in the San Fernando Valley, about 32km north of downtown Los Angeles, fire officials said.
The fire grew from 60 acres to 4 700 acres overnight, prompting evacuation orders for more than 100 000 people in the area.
Los Angeles Fire Department Chief Ralph Terrazas said the blaze was being fuelled by dry conditions and high winds known as the Santa Ana winds.
"Do not wait to leave. If we ask you to evacuate, please evacuate," he urged residents.
He said some 1 000 firefighters were fighting the blaze that was zero percent contained in early morning and which forced the partial shutdown of several major highways.
The metro line in the area was also shut down.
"We've calculated that the fire is moving at a rate of 800 acres per hour," Terrazas said, adding that it would probably take days to get it under control.
Some 200 firefighters and helicopters were meanwhile battling the brush fire - dubbed the Sandlewood fire - that tore through the mobile home park.
There were no immediate reports of injuries, but authorities ordered some 1 900 homes in the area be evacuated.
The Los Angeles Police Department said it had declared a "citywide tactical alert".
Evacuation centres are open for those forced to leave their homes, said LA mayor Eric Garcetti.
In the dark
Weather forecasters have warned of more strong winds and "extremely critical fire" conditions Friday and state authorities have issued their highest fire alert - a red flag warning.
The wildfires erupted as California's largest utility, Pacific Gas & Electric (PG&E), implemented rolling power blackouts that affected some two million people in Northern California this week.
About 312 000 customers remained in the dark Friday as a result of the shutoffs designed to reduce the threat of wildfire that can be sparked by lines downed in heavy winds.
Many schools and universities were also closed in northern parts of the state as people stocked up on gasoline, water, batteries and other basics, with frustration mounting at the blackouts condemned by some as "third world."
"We're seeing a scale and scope of something that no state in the 21st century should experience," Governor Gavin Newsom said on Thursday, blaming decades of what he called neglect and mismanagement by PG&E.
"This is not, from my perspective, a climate change story as much as a story about greed and mismanagement over the course of decades," Newsom said. "Neglect, a desire to advance not public safety but profits."
PG&E has defended the outages as necessary for safety reasons and has said it will take days before power is restored to all customers as inspections must be conducted on power lines in all of the affected areas.
"This is not how we want to serve you but blackouts can happen again," Bill Johnson, the CEO of the company said on Thursday.
Last November, PG&E's faulty power lines were determined to have sparked the deadliest wildfire in the state's modern history, which killed 86 and destroyed the town of Paradise.