More than a week of record-breaking heat across California is fueling multiple destructive wildfires and worsening already critical conditions ahead of the fall fire season.
Officials braced for an intense fire season due to drought conditions in California. But experts say the heatwave – likely the longest and hottest since records began in September – is setting the stage for fires to spread much faster.
The scorching temperatures have created a “flash drying effect” by pulling all moisture out of trees, grasses and other vegetation, according to Brent Wachter, a meteorologist at the US Forest Service’s Geographic Coordination Center.
“We’ve had really low humidity and warm temperatures, not just during the day but throughout the 24-hour period, and that has led to increased flammability in the fields and pushed them into an ultra-flammable scenario,” he said.
In the foothills of the Sacramento Valley, dead fuel moisture levels have dropped to their lowest levels in about 25 to 30 years, Wachter said.
That’s the area where the mosquito fire doubled to more than 13,700 acres Thursday after sparking near Foresthill in Placer County two days earlier and prompting mandatory evacuation orders for about 2,500 people, according to the California Department of Forestry and Fire Protection provoked. More than 1,000 buildings were threatened and some homes were burned down, but officials didn’t have an exact number Thursday.
By Thursday afternoon, the fire had thrown up a huge cloud of pyrocumulus, leapt over the Middle Fork of the American River and burned its way toward the hamlet of Volcanoville in El Dorado County.
“It’s very hot. It’s dry and it’s burning in areas where people are,” said Chris Vestal, public information officer. “The top priority is to get people out of their homes and out of the area.”
The cause of the fire is under investigation, but Pacific Gas & Electric Co. filed a report revealing “electrical activity” on one of its transmission lines near where the fire broke out Tuesday night. The fire was not contained as of Thursday. Evacuation centers were set up at Bell Road Baptist Church in Auburn and Cool Community Church in Cool.
“A lot of that is during the nighttime hours, normally fires settle down, but they keep driving during a heatwave and are very active overnight,” Wachter said. “That’s the key difference that makes this time so unusual.”
Southern California is grappling with the Fairview fire, which grew to nearly 24,000 acres as of Thursday night with 5% containment, prompting officials to expand evacuation orders and issue increasingly dire warnings.
“I’ve never seen a fire like this burn in Riverside County in my career,” said John Crater, Cal Fire’s Temecula Division manager. “It’s a very persistent fire. It does things we just haven’t seen before.”
Officials expect 22,000 people to be evacuated from the area, Crater said, as forecasters warned that Tropical Storm Kay could bring winds of more than 50 mph to the burn zone. Strong winds combined with drought-stricken fuel could mean further explosive, unpredictable growth, and rain could bring the risk of mudslides.
Gov. Gavin Newsom on Thursday declared states of emergency for Riverside, El Dorado and Placer counties over the Fairview and mosquito fires.
Wildfire activity has also been amplified by the amplifying effects of climate change, which have made fires bigger, more catastrophic, and burn longer, according to UC Merced fire scientist Crystal Kolden, a former US Forest Service firefighter.
While a heatwave of this length and magnitude typically occurred in July in previous years, Kolden said it is significant that the current one occurred between late August and September.
“A heat wave like this in September is unusually late, especially with these high temperatures, and it’s really problematic for fires because it’s drier across the state now than it was in July, when we typically had the hottest temperatures in the country this year,” she said .
Though northern California typically begins to cool and see precipitation earlier in the fall than southern California, Kolden said climate change is making the prospect of a year-round fire season a reality in some parts of the state.
“NorCal has a summer fire regime and we’re seeing that easing in September and this heatwave means NorCal is still very strong,” she said. “It’s evidence that climate change is making the fire season much longer and that resources that are already few and far between will need to go well into the fall for longer periods.”
Meanwhile, the main fire season in Southern California usually begins in October and coincides with the arrival of the Santa Ana winds. But if the region doesn’t get enough rain during the October-September water year, those fires could continue into the winter.
“In recent years we’ve seen fires in Santa Ana in November and even December, which again is an effect of climate change,” Kolden said.
Although this fire season hasn’t been particularly bad compared to previous years, Kolden said even relatively tame wildfires are becoming increasingly deadly due to climate change.
“Decades ago, this would have felt like a really small season given the number of ignitions, and we didn’t have a massive lightning event that started a series of fires,” she said. “This was a quieter year but the fires that broke out were destructive and deadly. Climate change alters fires throughout the season.”
At least nine people have died from wildfires so far this season, including two dead in the Fairview Fire and four dead in the McKinney Fire, which broke out in the Klamath National Forest near California’s Oregon border in July and burned more than 60,000 acres .
John Schulz, who lives four miles from the Fairview fire, said his power was out and it was about 97 degrees inside on Monday. Schulz, who previously lived in Paradise and Quincy, witnessed the 2018 campfire.
“It’s the same thing: heat and drought create perfect situations for fires,” he said. “This will be my last summer in California.”
Temperatures are expected to be in the 90s and into the 100s from Long Beach to downtown Los Angeles and around Beverly Hills in most of Southern California on Friday, according to National Weather Service forecaster Carol Smith.
Two records for the date were broken Thursday at Los Angeles International Airport and Paso Robles. It was 97 degrees at LAX, beating his previous record of 93 degrees set in 1984. It was 108 at Paso Robles, beating his record of 106 degrees set in 2021.
Residents should expect to battle the heat through Friday night, although Smith said the heat warning could be extended due to “unusually high” overnight temperatures, which have reached into the 80s.
“We are in a drought and it has been very hot during the extended heatwave,” she said. “The vegetation is really dry. The excessive heat increases the likelihood that the fire will be dominated by a smoke plume, meaning it will grow very quickly in extreme fire behavior.”
The heatwave is expected to subside by this weekend, coinciding with Tropical Storm Kay, a storm system off the coast of Mexico that is expected to hit the state in the coming days. Rain is forecast for parts of LA County on Friday and is expected to hit northern California by Saturday.
Wachter said the storm system “could have two storylines” as the moisture surge, thicker cloud cover and higher humidity could help quell fire activity. On the other hand, downdrafts from the storm could form over the wildfires and “spread them erratically,” he said.
Officials are preparing for possible flooding during the storm near burn scars, Cal Fire spokesman Jon Heggie said.
“It’s a very unique situation that right now, as we speak, a large forest fire is burning and being hit by the remnants of a hurricane,” he said. “We could be fighting fires one hour and preparing for flooding the next.”
Lin reported from Los Angeles and Garrison from Sacramento. Times contributor Gregory Yee contributed to this report.
https://www.latimes.com/california/story/2022-09-09/record-heat-fueling-dangerous-fires-across-california-pushing-firefighters-to-limit California’s heat wave fueling destructive fires. The worst is yet to come, officials fear