The start of a prolonged and potentially deadly heat wave coincided with elevated fire conditions in Northern California, prompting Pacific Gas & Electric Co. to begin its first planned power outages of the year on Tuesday, which are expected to last at least through Wednesday.
Dangerous conditions are fueling several fires in the region, including one in Butte County that prompted evacuations and another in Napa County.
Downed power lines could prevent new fires from starting. Authorities are using whatever help they can get as winds, low humidity, dry vegetation and extreme heat combine for potentially perilous days. Despite the power outages, several wildfires broke out Tuesday in Northern California, at least two of which required evacuations.
“It’s a really bad combination, honestly, to have a potentially record-breaking heat wave that starts with dry northerly winds,” Daniel Swain, a UCLA climate scientist, said at a briefing Monday. “As if that’s not enough, of course we’re in the week of the Fourth of July,” which literally adds sparks to the combustible environment.
“Fasten your seatbelts,” he said. “I think the fire season in California is probably going to intensify significantly over the next five to seven days.”
PG&E, California’s largest electric utility, implemented public safety power outages Tuesday morning in eight counties (Butte, Colusa, Lake, Napa, Solano, Sonoma, Tehama and Yolo) “due to high winds and dry conditions,” according to the company’s website. The outages are aimed at preventing its equipment from starting fires in dangerous conditions.
PG&E said the power outages affected about 2,000 customers. It said in a statement that it had “delayed the start” of planned outages for about 10,000 others, mostly in Glenn and Shasta counties, “due to favorable weather conditions.”
Much of the Sacramento Valley and San Francisco Bay Area mountains remain under a red alert — issued for high fire danger — as well as an excessive heat warning Tuesday and Wednesday. The red alert warns of a combination of winds up to 30 mph, low humidity and high temperatures that “may contribute to extreme fire behavior,” according to the National Weather Service.
California firefighters are battling multiple wildfires, with at least nine burning since Sunday, including two Tuesday in Napa and Butte counties, which are facing conditions ripe for wildfires to spread. The wind-driven Toll Fire in northwestern Napa County near Calistoga quickly spread to 41 acres and forced evacuations, according to the California Department of Forestry and Fire Protection. The Thompson Fire in Butte County also forced evacuations Tuesday afternoon, spreading to about 100 acres in less than an hour, according to Cal Fire. Power lines in the area were down, authorities said.
Crews were also battling the Basin Fire, the state’s largest, which was burning more than 13,000 acres in the Sierra National Forest in Fresno County as of Tuesday morning. It was 17 percent contained, according to Cal Fire.
The fire is near the Balch camp, a remote community where more than 150 people have been evacuated. PG&E has electrical infrastructure there, but none of its facilities had been affected as of Tuesday morning, a spokesman said.
Firefighters began responding Monday to the McCain Fire in San Diego County, which had grown to 1,000 acres as of Tuesday morning and was 5% contained, according to Cal Fire. Local officials issued evacuation orders for communities near Campo that remained in effect as of noon Tuesday.
“Extremely hot weather is drying out vegetation, increasing the risk of wildfires,” Cal Fire warned on social media. “Avoid activities that could start a wildfire, such as parking on dry grass, dragging chains, or using equipment during the hottest part of the day. Remember, one less spark means one less fire.”
Swain said it was “essentially inevitable” that wildfires would start and grow during the heat wave, given the Fourth of July fireworks, high temperatures and the buildup of grass and brush that has dried out after exploding during two wet winters.
But officials are reserving their most severe warnings for extreme heat, which is expected to last a week or more in parts of the state.
“An exceptionally dangerous situation is expected to develop over the next week as we enter a potentially historic and deadly heat wave,” the National Weather Service’s San Francisco Bay Area office wrote in its excessive heat warning. “Several days of well-above-normal temperatures will result in compounding impacts to people and infrastructure, with the potential for many heat-related deaths. … An event of this size, magnitude and longevity will likely rival anything we have seen in the last 18 years.”
Extreme heat has become the deadliest weather event in California and the rest of the country as climate change has made heat waves more intense, longer and more frequent. Weather officials are urging people to take this week’s weather seriously.
“This is a prolonged heat event that will certainly raise serious concerns about heat-related illness if people don’t take proper precautions,” said Kate Forrest, a meteorologist with the National Weather Service in Sacramento. Forecasters are predicting triple-digit temperatures for several days, with little relief overnight.
Redding could break or tie its record for most consecutive days above 110 degrees, set over six days in 1978. The city is expected to reach at least 110 degrees Wednesday through Monday, with a peak of 116 degrees Saturday, Forrest said. It’s possible the heat could last even longer.
“I’m definitely going to get close to that record,” she said.
Fresno could also break the record for consecutive days above 110. Temperatures are expected to reach or exceed that temperature Wednesday through July. The National Weather Service is also predicting several daily records over the next week in the San Joaquin Valley, where temperatures will remain in the triple digits for several days.
The excessive heat warning will be in effect throughout the weekend in most areas. Different regions will be under separate heat warnings, tied to their specific forecasts.
The heat wave in California comes as President Biden’s administration has stepped up its focus on “climate-fueled extreme weather events,” with federal officials announcing plans Tuesday to advance national heat protections for millions of workers and to hold a White House summit on extreme heat this summer.
“Summer has just begun; tens of millions of Americans are already under heat warnings. … Ignoring climate change is deadly, dangerous and irresponsible,” Biden said Tuesday in Washington. “More people die from extreme heat than from floods, hurricanes and tornadoes combined.”
Swain said it was almost trivial to point to the role of climate change in the California heat wave, although he said it was just one factor among many.
“Right now, all heat waves have a detectable human footprint,” Swain said. “In a warming climate, heat waves are becoming more frequent and intense virtually everywhere on Earth, so extreme heat events, like the one California is about to experience, are made worse and more likely by climate change.”
Many parts of the Central Valley are expected to see five to seven days of temperatures above 110 degrees and nighttime temperatures above 70 or 80 degrees, conditions that give bodies virtually no chance to recover.
While this heatwave is particularly dangerous in California’s interior, even the state’s coastal communities have been included in advisories this week. Temperatures in southern California’s western neighborhoods are expected to reach as high as 95 degrees, while in San Francisco, they could approach 90 degrees.
Rachel Uranga, Times staff writer and Jireh Ding contributed to this report.
