Wildfires are scorching thousands of acres in California and forcing tens of thousands of people from Los Angeles to wine country to evacuate.
California Gov. Gavin Newsom declared a state of emergency Friday in Sonoma and Los Angeles counties, where two of the most intense wildfires are growing.
The Tick Fire, which erupted on Thursday in Los Angeles County, has covered 4,300 acres and is only 5% contained. Fueled by ferocious 50 mph winds, it's threatening homes in Santa Clarita.
Flames jumped over a freeway overnight, lighting up guardrail posts like tiki torches and illuminating the way for firefighters.
#TickFire Night Operations water drops assisting with structure procreation and perimeter control @LACoFDPIO @Angeles_NF #LAWind @LASDHQ @CHP_HQ @SCVSignal media has permission w credit. Follow @LACoFDPIO for official information pic.twitter.com/P9WkbT4a3q— Michael Dubron (@MichaelDubron) October 25, 2019
More than 600 firefighters have been on the scene, racing from one house to another and extinguishing brush fires that are threatening homes.
Police officers went door-to-door in the middle of the night, telling residents to leave. About 50,000 people were ordered to evacuate.
All Los Angeles Unified School District campuses in the San Fernando Valley were closed Friday as the blaze raged on.
The fire's cause is unknown.
VIDEO: @LACoFireAirOps Firehawk helicopters fighting wildfire on three fronts. Working to protect lives and property earlier in Santa Clarita, CA. #TickFire @LACoFDPIO (media ok to use with credit) pic.twitter.com/XZEOlS3ZxL— LACoFireAirOps (@LACoFireAirOps) October 25, 2019
Red flag warnings remained in effect across Southern California Friday.
"The erratic winds today pose a challenge for our firefighters as they may change direction and intensify, posing a greater threat to homes," Cal Fire officials said Friday morning.
Winds were easing in the Los Angeles area but high winds continued from San Diego County to San Bernardino through Friday afternoon.
Fires also have erupted in San Bernardino County and San Diego County.
Another round of Santa Ana winds could return to Southern California by late Sunday or early Monday.
Meanwhile, hundreds of miles north, in Sonoma County -- the heart of Northern California's wine country -- the Kincade Fire has consumed 21,900 acres and is just 5% contained.
About 2,000 people are under mandatory evacuation orders, and the blaze has destroyed at least 21 homes.
Pacific Gas & Electric Co., the massive California utility, preemptively turned off power to about 28,000 customers in Sonoma County on Wednesday in an attempt to avoid fires.
The utility also said in a statement there appeared to be a "broken jumper" on a transmission tower near where the Kincade Fire is believed to have started.
And for parts of Northern California, the worst may be yet to come as strong, dry winds are forecast to move into the region this weekend.
Winds could reach 60 mph near Sacramento and Redding Saturday night and into Sunday.
#RedFlagWarning in effect today through Monday throughout California due to gusty winds and low humidity. This is #CriticalFireWeather and caution should be used when outdoors. https://t.co/TRIM6OtIun pic.twitter.com/1WFbknEbBq— CAL FIRE (@CAL_FIRE) October 25, 2019
The National Weather Service said this next round of dangerous weather that stokes fires in the region could be the strongest of the year, possibly the worst wind event since the 2017 Wine Country fires.
"The weather event could be the most powerful in California in decades," PG&E officials said Friday.
PG&E, which provides electricity to millions of Californians, has warned that the weekend may bring one of its biggest planned power shutoffs.
About 850,000 customers across 36 counties might lose power Saturday evening and stay in the dark for several days, the company warned Friday.
The preemptive shutoffs are for safety, the company said, to help prevent fires from sparking.
But the governor is criticizing PG&E for what he's called "years and years of greed" and "years and years of mismanagement."
"That greed has precipitated in a lack of intentionality and focus on hardening their grid, undergrounding their transmission lines. They simply did not do their job," Newsom said at a news conference Friday. "We will hold them accountable for the business interruption and costs."
PG&E was found responsible for dozens of wildfires, including last year's Camp Fire, the deadliest fire in state history. The Nov. 2018 Camp Fire in Northern California, which killed dozens, was sparked by power lines owned and operated by PG&E, Cal Fire said in May.
PG&E filed for bankruptcy after losing billions from the Camp Fire. The utility's stock on Friday sank more than 30% toward a record low.
"PG&E right now is very gun-shy of taking any risks" and doesn't "want to be liable if something goes wrong," Stephanie Pincetl, a professor at UCLA's Institute of the Environment and Sustainability and director of the California Center for Sustainable Communities, told ABC News earlier this month. "They're trying to manage their risk."
"PG&E has a very, very, very extensive grid," Pincetl said. "So it means that you have hundreds of thousands of miles really of transmission that you need to be very vigilant about in keeping upgraded, and that includes brush clearing."
The preemptive shutdowns also show "that PG&E, the public utilities commission and regulators have not really worked to figure out strategies to mitigate the potential of wildfire driven by our electricity infrastructure," Pincetl said.
"The utilities have known for awhile now, I would say several years," Pincetl added, "that change in climate and the accumulation of brush around the pathways of the grid lines that there is an increased chance of wildfire being caused by a spark from the grid or some other incident."
ABC News' Alyssa Pone and Jenna Harrison contributed to this report.