California’s wildfires have gotten much worse in the past two decades, researchers say. But certain circumstances came together in what one expert described as an “environmental recipe” that provided the breeding ground devastating mountain fire in Ventura County.
And researchers say it’s part of a disturbing trend.
More than 10,000 people have fled their homes as firefighters this week aimed at saving lives when the fire first broke out Wednesday morning. At least 10 people were injured, some from smoke inhalation during an American Red Cross event said spokesperson nurses at a night shelter treated people for scrapes and burns they suffered while trying to escape the flames.
A day after it started, California Governor Gavin Newsom declared a state of emergency in the county.
Within two days the time had come dozens of houses destroyed after searching over 20,000 acres, roughly the size of 32 square miles.
As firefighting efforts continue, experts three days later offered a glimpse into what caused the flames to spread quickly and the problems that made it difficult to control the blaze.
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An ‘environmental recipe’ for a rapidly progressing forest fire
The day before the mountain fire broke out, forecasters issued a notice relatively rare weather advice known as a “Particularly Dangerous Situation” Red Flag Warning, which says extremely dry, windy weather could lead to “volatile” and “extreme” fire growth.
Once the wildfire started, strong Santa Ana winds blew the flames away and much of the dry brush that had built up during a particularly wet winter kept them actively burning, said Drew Smith, assistant chief of the Los Angeles County Fire Department and fire behavior analyst.
“We are coming off two years of above-average rainfall, which gives us a very robust grass component,” Smith said. “And those fine fuels that are receptive to warm, dry and windy weather support the recipe for supporting large fire growth when there are high winds.”
“So if we have that environmental recipe to promote this, it’s because of the responsive fuel bed,” he said.
How Smith described the situation when he spoke to reporters Thursday echoed what another expert said a day earlier when the fire broke out. Dr. Josh Fisher, a climate scientist at Chapman University, also said a wet winter combined with very dry bushland was to blame, while broader implications of climate change also played a role. And it’s part of a broader trend, he said.
“We’re seeing a lot more wildfires for a lot of reasons,” Fisher said. “The general angle of climate change is that things are getting hotter and drier, but also remember that we have just had a very wet winter, also related to climate change. So this wet winter has caused a lot of plants and a lot of plants have grown.” vegetation that dried out in the summer.”
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Why fires can be worse in fall and winter
Another factor is the time of year. With the Santa Ana winds that come into Southern California in the fall, the flames are pushed forward and embers that spark flames can be blown into the air and carried up to three miles by the strong gusts, Smith said. And fall brings particularly low humidity, including the dry seasonal winds, making the terrain ripe for extreme fire growth.
Such environmental factors, which not only intensify the fires but also make them more difficult to fight, do not exist in summer.
“Fires during the summer do not occur in a wind-dominated environment,” Smith said, also noting dry conditions as a contributor.
In Southern California, the peak fire season typically runs from late spring, around May and June, through October, according to the Western Fire Chiefs Association (WFCA), which notes that climate change is leading to a longer and later fire season in the state. , a well-known consensus among researchers. Like Smith, the WFCA says wildfires can be more difficult to extinguish in the fall and winter, making them often more destructive than summer fires, according to the organization.
“It is a common misconception that the most dangerous time for fires in California is the months of July and August,” the WFCA website says. “While there may be fewer fires in September and October, the fires that do occur are much more destructive and burn many more hectares. This explosive effect is due to a combination of dry vegetation from hot summer weather and intense dry winds blowing. across the state during the fall.”
The most destructive wildfires in Ventura County both occurred in the winter months.
The Woolsey Fire broke out in November 2018 and eventually three people killed and destroyed 1,643 structures while burning nearly 97,000 hectares. Meanwhile, the 281,893-acre Thomas Fire – then the largest ever recorded in California history – erupted in December 2017, killing two people and destroying 1,063 structures as it tore through an area of Ventura County near where the Mountain Fire is burning.
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Wildfires have become increasingly worse in recent years
The California Department of Forestry and Fire Protection began recording wildfires and the destruction and death they cause in 1932.
More than half of the state’s 20 largest fires since then have occurred in the past decade, while 15 of the 20 most destructive wildfires have occurred in the past decade, according to Cal Fire. The deadliest fire in recorded state history was the campfire in Butte County in Northern California, which broke out in the winter of 2018 and killed 85 people.
This year, the Park Fire burned through four Northern California counties, becoming the state’s fourth largest ever.
It’s part of a disturbing trend that researchers say is due to long-term changes in the weather caused by climate change.
“We’re getting hotter, drier air, which makes it easier for fires to start,” said Glen MacDonald, a professor of geography at UCLA and lead author in a research paper published last year. “It makes the fuel much drier and the fires spread faster. They are more intense and harder to fight.”
The UCLA research paper notes that less winter rainfall, another effect of climate change, has also led to more fires.
