Updated at 1:50 a.m. ET on Wednesday
Firefighters knew their respite would not last in Northern California.
There, in Sonoma County, the massive Kincade Fire has consumed more than 75,000 acres — well over twice the size of San Francisco — in a span of six days. And after a brief lull overnight, the gusty winds that have been powering the blaze are expected to roar back to life by Tuesday evening.
The National Weather Service in the Bay Area is warning that the return of those winds, combined with continuing low humidity and high temperatures, will offer ideal conditions for the fire's spread Tuesday morning into Wednesday afternoon.
"We're in this critical 24-hour window," Ryan Walbrun, a meteorologist with the NWS, said at a news conference Tuesday. "We're hopeful that after we get through this wind event, things do look favorable for the next five to seven days."
The short-term forecast is unwelcome news for the more than 4,500 fire personnel who are assigned to battle the blaze, and who have struggled through steep terrain and narrow roads to bring the fire to just about 15% containment. So far more than 120 structures have been destroyed, and two firefighters have been injured. No fatalities have been reported.
Fire officials say they don't expect to have the wildfire fully contained until Nov. 7.
Pacific Gas & Electric, saying it's also alarmed by the fire-friendly conditions on the horizon, announced that it is expecting to perform another round of mass power shutoffs. Fresh on the heels of implementing a power blackout zone affecting nearly 1 million customers, the embattled utility says nearly 600,000 customers across Northern and Central California — some of whom already saw their power cut in a previous round — will feel the effects of the shutoffs planned Tuesday through Wednesday.
The company says the outages are meant "to prevent a catastrophic wildfire sparked by electrical equipment during extreme weather events." But that assertion has brought skepticism from state authorities.
"Look, we've had a decade-plus of mismanagement of our largest investor-owned utility, PG&E — greed and complete dismissal of public safety," Gov. Gavin Newsom told NPR in a phone call. "And as a consequence of that lack of investment, they've got a grid that is not modern."
The outages also have drawn concern at the federal level. U.S. Secretary of Veterans Affairs Robert Wilkie sent a letter to Newsom on Monday urging him to curb the power outages, saying they "could become dangerous for Veterans receiving in-home care and those who rely on the refrigeration of life saving medications like insulin."
Meanwhile, hundreds of miles to the south, firefighters are racing to contain another blaze: the Getty Fire, which erupted early Monday morning in Los Angeles. Perched near Interstate 405, the busiest highway in the U.S., the fire afforded some spectacular — and spectacularly frightening — views for passing motorists, even as it forced the evacuation from thousands of residences across the hills of northwestern Los Angeles.
The L.A. Fire Department said Tuesday morning that the Getty Fire, which had grown to more than 650 acres, remains just 5% contained. And with strong winds expected to reach up to 70 mph by Tuesday night, firefighters fear that embers riding the gusts could significantly complicate their fight to get the blaze under control.
"This fire will not be down and done for at least a couple weeks," Mayor Eric Garcetti warned at a news conference Tuesday morning.
Late Tuesday, investigators from the Los Angeles Fire Department's Arson-Counterterrorism Section, said they had determined a preliminary cause of the Getty Fire: "a tree branch that broke off during the high wind conditions and subsequently landed on nearby powerlines, which resulted in sparking and arcing that ignited nearby brush," according to a statement.
NPR's Eric Westervelt contributed to this report.