California Governor Gavin Newsom has requested an investigation into Los Angeles's dry fire hydrants, which have been blamed for worsening the firestorm that has left sections of the city in rubble.
Authorities are also investigating problems with the city's emergency warning system, which has been repeatedly sending false evacuation alerts to mobile phones across the area.
Tens of thousands of Californians are still under evacuation orders as three monster blazes continue to rage.
Firefighters, helped by calmer conditions, have made some progress towards bringing them under control, but "critical fire weather" is continuing.
Strong gusts and dry conditions were expected to fuel existing fires and new starts, the National Weather Service said on Friday, local time. More dangerous fire weather was possible next week, it said.
The official death toll now stands at 11.
US President Joe Biden has warned it will probably rise.
"Whether significantly or not, we don't know yet," he said. "There's still a lot of people who are unaccounted for."
Questions over dry hydrants
Reports of low water pressure and dry fire hydrants in some of the fire zone's worst affected areas have intensified anger among residents.
Mr Newsom used social media to announce an investigation into the water supply issues, to be conducted by state water and firefighting officials.
"We need answers to ensure this does not happen again and we have every resource available to fight these catastrophic fires," he said on X.
In a letter to local water and public works bosses, which he also shared online, Mr Newsom said reports of the dry hydrants and low water pressure were "deeply troubling".
"Losing supplies from fire hydrants likely impaired the effort to protect some homes and evacuation corridors," he wrote.
[newsom tweet]US president-elect Donald Trump has blamed mismanagement by the state's Democratic leadership for the water issues.
But officials have pointed to causes including proactive power cuts that shut down water pumps, fire damage to plumbing infrastructure, and overwhelming demand that was worsened when winds grounded water-bombing aircraft.
They also say hydrants are not suited to fighting wildfires, and are intended for smaller structure fires.
Mr Newsom has invited Trump to California to see the devastation and meet first responders.
"We must not politicise human tragedy or spread disinformation from the sidelines," the governor said in a letter to the president-elect.
Apology for false alerts
Californian authorities have apologised for the incorrect evacuation alerts that have spread further panic among the city's traumatised residents.
Mass messages have been sent to mobile phones across the Los Angeles County, including locations unaffected by the fires, saying: "An EVACUATION WARNING has been issued in your area."
"There is an extreme amount of frustration, anger, fear, with regards to the erroneous messages that have been been sent out through the wireless emergency alert system across LA County," local emergency director Kevin McGowan said.
"I can't express enough how sorry I am for this experience."
With so much of the city still in danger, authorities are imploring people not to disable their emergency messages, as they try to figure out what is going wrong with the automated system.
"We have every technical specialist working to resolve this issue and to find the root cause," Mr McGowan said.
"This is extremely frustrating, painful and scary, but these alert tools have saved lives during this emergency. Not receiving an alert can be a consequence of life and death."
The false-alarm alerts represent a new problem for emergency management teams already overwhelmed by the fires, deemed the most destructive in LA history.
On Friday afternoon, local time, the "Palisades fire" on the Pacific coast and the "Eaton fire" north-east of the city were still almost completely uncontained. They had destroyed or damaged at least 9,000 buildings and vehicles, according to official estimates.
The newer "Kenneth fire", in the hills north-west of LA, was about 35 per cent contained, fire officials said.
Suspected looting and arson were also compounding the disaster.
The Los Angeles Police Department confirmed a person was taken into custody after being detained by residents who suspected they were trying to start a fire in the Woodland Hills community.
The suspect was released after police determined there was not enough evidence to arrest them, but the LAPD said the investigation was ongoing.
An evening curfew imposed in areas around the Palisades and Eaton fires was meanwhile being enforced with zero tolerance, Sheriff Robert Luna warned.
It followed about 20 arrests for looting and related crimes.
"We are not screwing around with this," Sheriff Luna said.
"We don't want anyone taking advantage of our residents that have already been victimised."
Entire neighbourhoods have been devastated by the Palisades fire. (AP: Jae C. Hong)
Only a few vehicles escaped unscathed in this Malibu neighbourhood. (AP: Mark J. Terrill)
Beachfront properties along the coast in Malibu were also ravaged by fire. (AP: Jae C. Hong)
The Pacific Palisades fire has produced apocalyptic scenes. (ABC News: Cameron Schwarz)
