As California braces for a dangerous, prolonged heat wave that’s expected to last through next week, firefighters across the state are battling several new wildfires, some serious enough to force evacuations.
The most dangerous fire was burning in Oroville, where crews on Wednesday were fighting the Thompson fire under an excessive-heat warning, with temperatures forecast to reach up to 109 degrees and wind gusts up to 30 mph.
The fire spurred an evacuation order affecting thousands in and around the city and in Butte County after it broke out just before 11 a.m. Tuesday, according to Dan Collins, a fire captain at the California Department of Forestry and Fire Protection’s Butte County station.
The fire had grown to 3,002 acres by Wednesday morning, is threatening about 230 structures and is 0% contained, Cal Fire officials said.
Images on social media and local news outlets showed several buildings burning in Oroville, but the exact number of structures that had been engulfed was unclear.
The heat wave is currently spanning 21 states, with 110 million people under a heat advisory, watch or warning, the National Weather Service’s Weather Predict Center said in a Wednesday morning forecast.
Temperatures will remain above average across California this week, with highs up to 115 degrees in places, according to the forecast.
“Dozens of record highs are possible, expressing the rarity of this early-July heat wave,” the forecast said. “The duration of this heat is also concerning as scorching above-average temperatures are forecast to linger into next week.”
Much of Northern California remains under a red flag warning — an alert for extreme fire weather — as well as an excessive heat warning Wednesday. The red flag alert warns of a combination of winds up to 30 mph, low humidity and hot temperatures that “can contribute to extreme fire behavior,” according to the National Weather Service.
Nine new fires ignited in the region Tuesday, according to Cal Fire. The Thompson was the largest, followed by the Airline fire in San Benito County, which was at 1,150 acres and 55% contained Wednesday morning.
Given the conditions across its coverage area, Pacific Gas & Electric Co. initiated its first public safety power shutoffs of the year, affecting 2,000 customers across eight counties — Butte, Colusa, Lake, Napa, Solano, Sonoma, Tehama and Yolo. The shutoffs, which are expected to last at least through Wednesday, are meant to prevent the utility’s equipment from sparking fires during dangerous conditions.
Fire crews in Butte County had one advantage: The Thompson fire is burning close to Lake Oroville, allowing water-dumping helicopters to make “quick turnarounds” between the massive reservoir and the front edge of the blaze, Cal Fire said.
In Napa County, north of Calistoga, the Toll fire began just before 10 a.m. Tuesday and had grown to about 50 acres by the afternoon, according to Cal Fire.
The wind-driven fire closed at least one road in the area and prompted several evacuation orders and warnings, affecting just over 100 people in the area, according to Jason Clay, a Cal Fire spokesperson at the Sonoma-Lake-Napa station. By evening, crews had managed only 15% containment of the fire.
The conditions in the area are ripe for further wildfires to erupt, Clay said.
“The grasses are really dry,” said Clay, who also noted the area’s red flag warning. “That combination is all aligning, [and] that could lead to extreme fire behavior.”
Fire officials have continued to warn that once vegetation fully dries out — typically by midsummer — wildfires could ramp up, given the profusion of grass and brush that grew after two winters with heavy precipitation.
“Avoid activities that could spark a wildfire, such as parking on dry grass, dragging chains, or using equipment during the hottest parts of the day. Remember, one less spark means one less fire,” Cal Fire advised on social media.
Daniel Swain, a UCLA climate scientist, called it “essentially inevitable” that wildfires would continue to start and grow during the heat wave — which was just getting started — given the threat of further fire starts from the holiday weekend’s fireworks and firecrackers, the hot temperatures and the buildup of dry fuels.
“It’s a pretty bad combination, honestly, to have a potentially record-breaking heat wave that starts off with dry north winds,” Swain said in a briefing Monday. “Buckle up: I think California’s fire season is likely to escalate considerably over the next five to seven days.”
In eastern San Diego County, another large fire continued to grow after sparking Monday. The McCain fire, burning just off Interstate 8, was 30% contained Tuesday night, having scorched 1,362 acres, according to Cal Fire. The fire had prompted multiple evacuation orders and warnings, affecting about 140 people, according to Mike Cornette, a fire captain with the San Diego County Cal Fire team.
Authorities closed a section of the westbound lane of Interstate 8, but the eastbound lane remained open, Cornette said. The cause of the fire is still under investigation, but Cornette said it was probably sparked by a traffic collision that caused a vehicle to become engulfed in flames. He said about 150 structures were threatened, but none had been damaged.
“Right now, there’s not a whole lot of smoke coming off the fire, but the fire is still active,” said Cornette, who expected that it would take several more days before it was fully contained.
Two other small fires also sparked Tuesday in Northern California: the Denverton fire in Solano County and the Yolla fire in Shasta County, both smaller than 30 acres as of Wednesday morning.
Crews also were still fighting the Basin fire Wednesday, which had burned 13,819 acres in the Sierra National Forest in Fresno County. It was 26% contained, according to Cal Fire.
That blaze is burning not far from the Balch Camp, an isolated community from which more than 150 people were evacuated because of the flames. PG&E has power infrastructure there, but a spokesperson for the utility said none of its facilities had been affected as of Tuesday morning.
Times staff writers Joseph Serna and Rachel Uranga contributed to this report.