When the state fire department recently announced that the fire at the CZU Lightning Complex had quadrupled in just one day, an audible gasp rose from the audience.
Although lightning fires have scorched the state since prehistoric times, the speed at which the SCU and LNU lightning complex fires became the second and third largest flames ever recorded in California has terrified emergency officers and strained fire-fighting resources. The fires killed seven people, destroyed more than 2,100 buildings and made the air in the Bay Area unhealthy.
And it could only get worse in the future, experts say.
"There is a direct relationship between heat and fire, and increasing heat has been inevitable for at least several decades," said Michael Gerrard, director of Columbia University's Sabin Center for Climate Change Law. "If you like 2020, you will love 2050."
Why did this year's fires burn more than 1.4 million acres of the state's scenic coastal mountains and hills surrounding the wine country? After all, the lightning siege of 2008, when nearly 800,000 acres burned, was the first time in 40 years that the National Guard was called in because resources were stretched to the limit.
The answer is complicated.
The fate of all wildfires is determined by the fire behavior triangle – fuel, weather, and topography – according to Craig Clements, professor at the San Jose State Fire Weather Research Laboratory.
However, other factors were also involved in this latest outbreak. A summer heat wave exacerbated by climate change combined with tropical humidity and storm energy to create thunderstorms. The resulting lightning strikes have struck a region with a history of difficult firefighting and another area that has experienced numerous fires in the recent past.
A burned vehicle stands outside a fire-ravaged residence in Boulder Creek as smoke from the fire at the CZU Lightning Complex fills the sky.
(Marcio Jose Sanchez / Associated Press)
The state and locally maintained coastal mountains in central California where the CZU Lightning Complex burns have a long history of challenging firefighters. In 2016, a firefighter died in Monterey County north of the current fire trying to contain the persistent Soberanes fire that burned 50 homes while the flames lived for months in the area's steep canyons and impassable terrain.
In 2003, south of Livermore, where part of the SCU Lightning Complex is on fire, 53 firefighters were overrun in the middle of the night and used their shelters in what is possibly the second largest shelter that crews had deployed in US history. Said Clements.
In both cases, as now, the temperatures did not drop significantly overnight, nor was the sea moisture reintroduced into the higher elevations of the landscape. In the summer, a high pressure system settles over the Pacific and spins to direct warm, dry air over the upper elevations of the coastal area while pushing cool, moist air into the ocean below, San Jose state atmospheric scientist Alison said Bridger.
"It's basically why it doesn't rain in summer," she said.
If you use an extreme heat wave, the risk of fire increases significantly.
"The fact that we have had such extremely large, rapid, devastating fires with no offshore winds is very unusual," said UCLA climate researcher Daniel Swain. "All of this suggests something that we know to be true … the state of the vegetation, the state of the fuels, has been quite exceptional."
Most of the areas burning in the three fires of the lightning complex are classified as moderate to severe drought, according to the latest report by the US Drought Monitor released on Thursday. Huge chunks of every fire's footprint encompass areas that have not had fires in decades and the jackpots were made of dead and dry tinder.
"Unfortunately, as the climate continues to warm, the table is set more often for these extreme fires," said Swain. "It means the ceiling on how bad these fires can be continues to rise."
The night the thunderstorm, hundreds of miles wide, started all of these fires, a pre-sunrise "heat surge" broke through parts of the wine country and left pre-dawn temperatures between 80 and 100 degrees in areas like Travis Air Force Base rise under two hours. While experts say it likely didn't have a direct impact on the fires, it certainly didn't help and foresaw the challenging conditions to come.
In this long exposure photo, flames consumed part of Lake Berryessa during the Hennessey fire in the Spanish apartment in Napa that is part of the LNU Lightning Complex fire.
(Josh Edelson / AFP / Getty Images)
From Tuesday through Wednesday, winds poured from the mountains between Oregon and California into the Sacramento Valley, releasing moisture. By the time they reached the hills of the wine country, they were bone dry and affected the explosive growth of the fire, said National Weather Service meteorologist Cory Miller. The LNU Lightning Complex fire increased tenfold in 36 hours from 12,200 acres on the morning of August 18 to 124,000 acres the following night, according to the California Department of Forestry and Fire Safety.
Sarah Johnson and the Emerald Hills Horse Ranch in the winter were on the trail of fire.
Johnson, 29, is originally from Ohio and has experienced thunderstorms. Two weeks ago she was stepping back in a hammock enjoying the taste of the Midwest when lightning flashed over the horizon around Berryessa Lake and the mountain. Vaca.
But soon the storms were replaced by smoke and then falling ash. Johnson and her boyfriend were tapping their cell phones, listening to first aiders scanning traffic over the movement of the fire. The California Department of Forestry and Fire Safety website was intermittent, overwhelmed by a surge in web traffic from around the world.
When the fire rose that night on August 18th and 19th, Johnson's friend's phone rang incessantly. The ranch boarders tried to reach him to warn him of the incoming fire.
The couple woke up and took action, waking up neighbors, inviting horses in when trailers arrived, and helping knock down small fire pits in the ranch pasture. The ranch lost energy at some point during the fight.
"It was incredibly windy and smoky and you could see a fire tornado forming and the rate of spread was incredible," said Johnson. "The fire was just so bright that we could see everything."
Flames from the LNU Lightning Complex fire consume an unincorporated Napa County home.
(Noah Berger / Associated Press)
For the next few hours, their neighbors' houses burned. The fire was quick and the county's emergency alert system didn't reach many of them until it was too late, if at all, Johnson said.
"I remember at one point just stopped and looked and said," Where are all the fire trucks? "And it was just another surreal moment and I realized that no one was coming," she said.
There is concern that as these fires hit the same areas over and over again, they will change California permanently, and not for the better.
A moderate fire can clear underbrush and competing trees, and give a healthy forest room to breathe. But when it's kept revisiting – as has happened in parts of Napa County in recent years – those native grasses and plants give up the fight and invasive plants move in, much like what happens in Southern California. Often times, these new species can spread the fire faster.
California has choices to make as fire is inevitable and megafires are increasingly possible, said Gerrard, the director of climate law in Colombia. Building codes can be updated. The supply infrastructure can be modernized and better regulated. Decisions about where to build houses and how to manage forests can be made with the fire hazard and local ecology in mind.
"It's very much like a managed retreat on the coast," Gerrard said. "The hope is that recurring, related disasters will be a wake-up call."