Science
Earthquake risks and rising costs: The price of operating California's last nuclear plant
Under two gargantuan domes of thick concrete and steel that rise along California’s rugged Central Coast, subatomic particles slam into uranium, triggering one of the most energetic reactions on Earth.
Amid coastal bluffs speckled with brush and buckwheat, Diablo Canyon Nuclear Power Plant uses this energy to spin two massive copper coils at a blistering 30 revolutions per second. In 2022, these generators — about the size of school buses — produced 6% of Californians’ power and 11% of their non-fossil energy.
Yet it comes at almost double the cost of other low-carbon energy sources and, according to the federal agency that oversees the plant, carries a roughly 1 in 25,000 chance of suffering a Chernobyl-style nuclear meltdown before its scheduled decommissioning in just five years — due primarily to nearby fault lines.
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As Gov. Gavin Newsom’s administration looks to the aging reactor to help ease the state’s transition to renewable energy, Diablo Canyon is drawing renewed criticism from those who say the facility is too expensive and too dangerous to continue operating.
Diablo is just the latest in a series of plants built in the atomic frenzy of the 1970s and ’80s seeking an operating license renewal from the federal Nuclear Regulatory Commission as the clock on their initial 40-year run ticks down. As the price of wind and solar continues to drop, the criticisms against Diablo reflect a nationwide debate.
Tom Jones, right, a regulatory and environmental senior director at PG&E, and Jerel Strickland, a senior licensing and spent nuclear storage consultant, walk past one of two massive turbine-generator units inside the turbine building at Diablo Canyon Nuclear Power Plant recently.
(Genaro Molina/Los Angeles Times)
The core of the debate lives in the quaint coastal town of San Luis Obispo, just 12 miles inland from the concrete domes, where residents expected Diablo Canyon to shut down over the next year after its license expired.
Instead, Newsom struck a deal on the last possible day of the state’s 2021-22 legislative session to keep the plant running until 2030, citing worries over summer blackouts as the state transitions to clean energy. The activists who had negotiated the shutdown with PG&E and the state six years prior were left stunned.
Today, the plant is still buzzing with life: Nuclear fission, in the deep heart of the plant, continues to superheat water to 600 degrees at 150 times atmospheric pressure. Generators continue to whir with a haunting and deafening hum that reverberates throughout the massive turbine deck.
Left untouched, nuclear fission erupts into a runaway chain reaction that can heat the core of a nuclear plant to thousands of degrees, liquifying the metal around it into radioactive lava.
So, operators have to constantly stifle the reaction to keep it under control.
In the event of an earthquake, they need to stop the reaction as quickly as possible. But if the shaking is so rapid and intense that the plant is critically damaged before it can shut down, operators could become helpless in preventing a meltdown.
Tom Jones, senior director of Regulatory Environmental and Repurposing at PG&E, talks about how the Diablo Canyon Nuclear Power Plant operates.
(Genaro Molina/Los Angeles Times)
Tom Jones, senior director of Regulatory Environmental and Repurposing at PG&E, is reflected in a display that explains the fission process at Diablo Canyon Nuclear Power Plant recently.
(Genaro Molina/Los Angeles Times)
Diablo Canyon is built to endure specific intensities and speeds of shaking — but predicting how likely an earthquake is to exceed those specifications is no easy task. Earthquakes are the result of deeply complex underground motion and forces, and they’re notoriously chaotic.
In order to start estimating the seismic safety of the plant, geophysicists have to understand: first, where the faults are; second, how much they’re slipping to trigger earthquakes; and finally, when those quakes hit, how much shaking they cause.
Earthquakes account for about 65% of the risk for a worst-case scenario meltdown. Potential internal fires at the plant make up another 18%. The last 17% is made up of everything from aircraft impacts and meteorites to sink holes and snow.
In assessing the likelihood of all these threats, the Nuclear Regulatory Commission estimates that in any given year, each of Diablo Canyon’s two reactor units has a roughly 1 in 12,000 chance of experiencing a nuclear meltdown similar to Japan’s Fukushima disaster.
Likewise, there’s about a 1 in 127,000 chance a failure will cause the plant to release exorbitant amounts radioactive material into the atmosphere before residents could evacuate, creating a Chernobyl-style disaster.
This means that, every year, nearby residents have roughly the same chance of seeing a nuclear meltdown as dying in a car crash. Also, in any given year, they’re about 50 times more likely to face a mass-casualty radioactive catastrophe than get struck by lightning.
Diablo Canyon employees work around the clock to ensure the risk is as small as possible. “Our safety culture, it’s always on the top of my mind,” said Maureen Zawalick, the vice president of business and technical services at Diablo. “It’s in my DNA.”
Maureen Zawalick, PG&E Business and Technical Services vice president, in her office at the Diablo Canyon Power Plant.
(Genaro Molina/Los Angeles Times)
The plant is the only one in the U.S. with a dedicated geoscience team that studies the region’s seismic landscape. And like other nuclear facilities, Diablo has done countless tests on its equipment, hosted walkthroughs with regulators to identify possible points of failure and generated thousands of pages of analysis on the facility’s ability to withstand the largest earthquake possible at the site.
Earthquake precautions include massive metal dampers that are fixed to essential infrastructure, such as the duct carrying the control rooms’ air supply. In the event of a tremor, monstrous concrete pillars penetrate deep into the bedrock to keep the building and essential infrastructure grounded. The hefty concrete walls reinforced with steel rebar as thick as a human arm safely distribute the forces throughout the structure to prevent critical cracks or collapses.
If the plant loses power, there are backup generators for the backup generators.
A worker pushes a utility cart past a billboard that lists employee goals at Diablo Canyon Nuclear Power Plant recently.
(Genaro Molina/Los Angeles Times)
Operators spend a fifth of their time on the job training for every possible nightmare. Diablo has a simulator on site that’s an exact replica of the Unit One control room. It’s capable of putting operators through the worst conditions imaginable. It shakes with the vigor of a real earthquake. The lights flicker and the analog dials spin back up as emergency power comes online.
For everyone working on site — including the senior leadership team — safety is personal. Should something go wrong, their lives are on the line.
“With any source of energy, there is risk,” said Zawalick. “All the independent assessments, all the audits, all the third party reviews, all of that …. is what gives me the confidence and the security and the safety of why I’ve been out here almost 30 years.” Her office is no more than 500 feet from the reactors.
“If there ever was an earthquake of any magnitude in this community,” she said, “I would grab my two daughters and we’d come here.”
Maureen Zawalick, PG&E Business and Technical Services vice president, looks out her office window at Diablo Canyon Nuclear Power Plant recently.
(Genaro Molina/Los Angeles Times)
Many critics charge that the risks are understated — due in part to a cozy relationship between industry and regulators. (Some scientists involved with one of Diablo Canyon’s two independent review organizations have collaborated on scientific papers with PG&E staff and funding.)
The Nuclear Regulatory Commission also oversees the plant and conducts its own investigations. In July, the government agency dismissed all three formal criticisms against Diablo’s seismic safety in the plant’s license renewal process.
Sam Blakeslee, a San Luis Opispo geophysicist and former state senator and Assembly member, has a list of technical concerns — primarily the lack of shaking data close to fault lines, which are used to inform the models that predict earthquake motion at the plant — but he likens the core of his concern to the NASA Challenger disaster.
NASA publicly touted a strong safety culture and low chances of things going wrong. Yet, the investigation found political and public pressures had corrupted the safety from the top down.
He argues this is a possibility for any large organization dealing with complex and potentially dangerous systems. Therefore, people need to constantly hold the plant accountable.
“That’s why I tend to try to make sure that the community voice is present,” he said, “ because we are the ones that will pay the price.”
In 2022, Newsom introduced a proposal to keep Diablo Canyon open past its two reactors’ 2024 and 2025 shutdown dates. His proposal, distributed to lawmakers just three weeks before the end of the legislative session, set off a flurry of negotiations among PG&E, the governor and the Legislature.
After discussion drew on past midnight, the Legislature passed the bill.
But it comes at a cost.
While the average price of solar and wind have dropped dramatically over the past 15 years, nuclear’s has been steadily rising. In 2009, solar cost three times what nuclear did, and wind was about even with it. Now, nuclear is over two times the cost of both renewables.
Technical advancements have slashed the price of renewable energy, but nuclear power has faced more outages, equipment replacements and increasingly stringent and expensive safety requirements in the wake of the Fukushima disaster.
One study from MIT researchers found that about a third of the increasing cost could be attributed to safety requirements from the Nuclear Regulatory Commission. They attribute another third to research and development projects for efficiency, reliability and safety improvements, and they assign the final third to a decrease in worker productivity — perhaps in part due to lower morale.
Twin containment domes rise above the facility as seen through a windshield on the drive to the Diablo Canyon Nuclear Power Plant.
(Genaro Molina/Los Angeles Times)
PG&E is estimating that Diablo Canyon will produce energy at $91 per megawatt-hour during its extension. (The average U.S. household buys about 10 megawatt-hours every year.)
However, the Alliance for Nuclear Responsibility argues the plant’s cost is even higher. David Weisman, the legislative director at the alliance, said PG&E is using optimistic predictions of its energy output for the extended period — 5% higher than previous years.
On top of that, the state gave PG&E a $1.4-billion loan to alleviate the initial costs of extended operations. But Wiesman said the funds don’t necessarily need to go toward offsetting the cost of running Diablo. The federal government agreed to reimburse the state up to $1.1 billion — depending on whether the plant meets specific operating criteria — and PG&E is expected to pay off the rest of the loan with profits.
While the loan isn’t a cost that consumers would see on their energy bills, taxpayers across the country could foot the bill. Weisman argued that it brings Diablo’s cost to a maximum of $115 per megawatt-hour — roughly double the cost of solar.
Yet Newsom argues that if California is to meet its goals of 60% renewable energy by 2030, Diablo needs to stay online in the meantime to ensure the state has reliable power amid heatwaves and wildfires.
Diablo Canyon essentially runs 24/7, providing constant power to the state (assuming it doesn’t have any issues, which it sometimes does). For solar to provide similarly constant power, the electric grid will require a massive expansion of its battery infrastructure to store the energy between the midday peak of energy production and the evening peak of energy use.
However, new studies are finding that energy storage is a feasible approach to grid reliability — and that even when adding the price of that infrastructure, solar still costs less than nuclear.
Tom Jones, a regulatory and environmental senior director at PG&E, talks about the number of days that Turbine Unit One has operated to bring power to California while inside the turbine building at Diablo Canyon Power Plant recently.
(Genaro Molina/Los Angeles Times)
Since Diablo’s extension was signed into law, California has almost doubled its battery storage. The state now has enough to supplement about a quarter of the state’s power needs for about half an hour during peak energy usage (although, in practice, it would likely supplement much less for much longer).
“That’s four or five Diablo Canyons,” said Weisman. Newsom should “save the people of California [billions of dollars] thrown down PG&E’s rat hole, declare triumphant victory in the renewable race and accept the laurels.”
Instead, at a recent press event announcing California had reached a fifth of its storage capacity goal, Newsom laughed off the idea that Californians will no longer have to worry about blackouts.
“We have a lot of work to do still in moving this transition, with the kind of stability that’s required,” he said. “So no, this is not today announcing that blackouts are part of our past.”
Diablo Canyon’s leaders and advocates view the plant as supporting California through this challenging transition period: It’s not perfect, but it provides the state with much-needed reliable, clean power, they say.
In a conference call shortly after Diablo’s initial 2024 shutdown date was negotiated, then-chief executive of PG&E Tony Earley acknowledged the plant would eventually become too expensive to operate.
“As we make this transition, Diablo Canyon’s full output will no longer be required,” he said.
Steam rises from the Pacific Ocean where an outfall of heated water from the Diablo Canyon Nuclear Power Plant pours into coastal waters.
(Genaro Molina/Los Angeles Times)
Zawalick said the Diablo team is ready to continue operating as long as the state needs it to. “Thinking about electrification, [electric vehicle] demand, continued drought, the temperatures we’re seeing, wildfires … tariffs — I mean, the list goes on,” she said. “That’s making the equation a bit challenging to see exactly when Diablo will shut down versus how long Diablo will be needed by the state.”
Science
A retired teacher found some seahorses off Long Beach. Then he built a secret world for them
Rog Hanson emerges from the coastal waters, pulls a diving regulator out of his mouth and pushes a scuba mask down around his neck.
“Did you see her?” he says. “Did you see Bathsheba?”
On this quiet Wednesday morning, a paddle boarder glides silently through the surf off Long Beach. Two stick-legged whimbrels plunge their long curved beaks into the sand, hunting for crabs.
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But Hanson, 68, is enchanted by what lies hidden beneath the water. Today he took a visitor on a tour of the secret world he built from palm fronds and pine branches at the bottom of the bay: his very own seahorse city.
The visitor confirms that she did see Bathsheba, an 11-inch-long orange Pacific seahorse, and a grin spreads across Hanson’s broad face.
“Isn’t she beautiful?” he says. “She’s our supermodel.”
If you get Hanson talking about his seahorses, he’ll tell you exactly how many times he’s seen them (997), who is dating whom, and describe their personalities with intimate familiarity. Bathsheba is stoic, Daphne a runner. Deep Blue is chill.
He will also tell you that getting to know these strange, almost mythical beings has profoundly affected his life.
“I swear, it has made me a better human being,” he says. “On land I’m very C-minus, but underwater, I’m Mensa.”
Hanson is a retired schoolteacher, not a scientist, but experts say he probably has spent more time with Pacific seahorses, also known as Hippocampus ingens, than anyone on Earth.
“To my knowledge, he is the only person tracking ingens directly,” says Amanda Vincent, a professor at the University of British Columbia and director of the marine conservation group Project Seahorse. “Many people love seahorses, but Roger’s absorption with them is definitely distinctive. There’s a degree of warm obsession there, perhaps.”
Rog Hanson keeps watch over a small colony of Pacific seahorses.
(Carolyn Cole / Los Angeles Times)
Over the last three years, Hanson has made the two-hour trek from his home in Moreno Valley to the industrial shoreline of Long Beach to visit his “kids” about every five days. To avoid traffic, he often leaves at 2 a.m. and then sleeps in his car when he arrives.
He keeps three tanks of air and his scuba gear in the trunk of his 2009 Kia Rio. A toothbrush and a pair of pink leopard print reading glasses rest on the dash.
Hanson makes careful notes after all his dives in a colorful handmade log book he stores in a three-ring binder. On this Wednesday he dutifully records the water temperature (62 degrees), the length of the dive (58 minutes), the greatest depth (15 feet) and visibility (3 feet), as well as the precise location of each seahorse. His notes also include phase of the moon, the tidal currents and the strength of the UV rays.
“Scientists will tell you that sunlight is an important statistic to keep down,” he says.
He has given each of his four seahorses a unique logo that he draws with markers in his log book. Bathsheba’s is a purple star outlined in red, Daphne’s is a brown striped star in a yellow circle.
Rog Hanson makes careful notes after all his dives. He has given each of his four seahorses a unique logo.
(Carolyn Cole / Los Angeles Times)
He’s learned that the seahorses don’t like it when he hovers nearby for too long. Now he limits his interactions with them to 15 to 30 seconds at a time.
“At first I bugged them too much,” he says. “I was the paparazzi swimming around.”
Hanson traces the origins of his seahorse story back nearly two decades to the early morning of Dec. 30, 2000.
He was diving solo off Shaw’s Cove in Laguna Beach when a slow-moving giant emerged from the abyss. It was a gray whale whose 40-foot frame cast Hanson in shadow.
The whale could have killed him with a flick of its tail, Hanson says, but he felt no fear. The two made eye contact and, as Hanson tells it, he felt the whale’s gaze peering directly into his soul.
It was all over in 10 seconds, but Hanson was altered. He had always wanted to live at the beach, but after this encounter, he vowed to make it happen. It took years —15, in fact — but he finally got a job as a special education teacher in the Long Beach public school system. He bought a van and parked it on Ocean Boulevard. He lived at the beach and dived every day for 3½ months before moving to Moreno Valley.
To amuse himself while he lived at the beach, he built an underwater city he called Littleville out of discarded toys he found at the bottom of the bay.
Hanson saw his first seahorse in January 2016 while checking on Littleville. It was bright orange, just 4.5 inches long, and Hanson, who had logged over a thousand dives in the area, knew it didn’t belong there.
Daphne is one of the seahorses that Rog Hanson is studying in Alamitos Bay.
(Carolyn Cole / Los Angeles Times)
The range of the Pacific seahorse is generally thought to extend from Peru to as far north as San Diego. This seahorse ended up about 100 miles north of that.
Scientists said the seahorse and others that joined her had probably ridden an unusual pulse of warm water up the coast, along with other animals generally found in southern waters.
“We were getting a lot of weird sightings in the fall of 2015,” says Sandy Trautwein, vice president of husbandry at the Aquarium of the Pacific. “There was a yellow-bellied sea snake, bluefin tuna, marlin, whale sharks — a lot of animals associated with warm water.”
Most of these animals eventually left after ocean temperatures returned to normal, but Hanson’s seahorses stayed.
That may be because Hanson had built them a home.
It happened like this: In June 2016 he watched in horror as more than 100 high school football players splashed in the shallow waters, right where his seahorses usually hung out.
“I thought, I gotta do something, I gotta do something,” he says.
“On land I’m very C-minus, but underwater, I’m Mensa.”
— Rog Hanson
Then he remembered that, back in the Midwest where he grew up, he used to help the city park service make “fish cribs.” In early spring they would use brush and twigs to build what looked like a miniature log cabin with no roof on an ice-covered lake. When the ice melted, the cribs would fall to the bottom, creating a habitat for fish and other animals.
“So I said to myself, build them a city that’s deeper, where feet can’t get to it even at low tide,” Hanson says.
And he did.
By July 2016 two pairs of seahorses had moved into the new habitat. Daphne, the runner, was named after the nymph from Greek mythology who flees Apollo, Kenny’s name came from the proprietor of a local kayaking company. “Bathsheba” was inspired by a Bible story, and her mate, Deep Blue, named after a dive shop that has helped sponsor Hanson’s work since he launched his seahorse study.
He’s seen Kenny’s and Deep Blue’s bellies swell with pregnancy and noted how their partners check in on them daily, frequently standing sentinel nearby. He’s visited the fish at odd hours to see how their behavior changes from morning to night. And he mourned when Kenny disappeared in January. He still hasn’t come back. (A new member, CD Street, arrived June 29.)
“It feels like I’m reading a book, the book of their life, and I can’t put it down,” he says.
He’s also reached out to seahorse scientists across the globe to compare notes. “I won’t say I know the most about seahorses in the world, but I know the people who do,” he says.
Amanda Vincent, the director of Project Seahorse, says that seahorses spark an emotional reaction in almost everyone.
Daphne is one of the seahorses that Rog Hanson is studying in Alamitos Bay. Hanson and Ashley Arnold keep watch over a small colony of Pacific seahorses.
(Carolyn Cole / Los Angeles Times)
“Remember those books with three flaps where you can mix the head of a giraffe with the body of a snake and the tail of a monkey? That’s what we’ve got here,” she says. “They appeal to the sense of fancy and wonder in us.”
When Mark Showalter, a planetary astronomer at the SETI Institute, recently discovered a moon orbiting Neptune, he named it Hippocamp in part because of his love of seahorses.
“I’ve seen them in the wild and they are marvelously strange and interesting,” he says. “It’s a fish, but it doesn’t look anything like a fish.”
Pacific seahorses are among the largest members of the seahorse family. Males can grow up to 14 inches long, while females generally top out at about 11. They come in a variety of colors, including orange, maroon, brown and yellow. They are talented camouflagers that can alter the color of their exoskeleton to blend into their environment.
“I won’t say I know the most about seahorses in the world, but I know the people who do.”
But perhaps their most distinguishing characteristic is that they are the only known species in the animal kingdom to exhibit a true male pregnancy. Females deposit up to 1,500 eggs in the male’s pouch. The males incubate the eggs, providing nutrition and oxygen for the growing embryos. When the larval seahorses are ready to be released, he goes into labor — scientists call it “jackknifing” — pushing his trunk toward his tail.
After three years of observation, Hanson has collected new evidence about seahorse mating practices. His research suggests that although most seahorses are monogamous, a female will mate with two males if there are no other female seahorses around.
He also found that males, who are in an almost constant state of pregnancy, tend to stick to an area about the size of a king-size mattress, while the females roam up to 150 feet from their home during a typical day.
Eventually, he may be able to help scientists answer another long-standing question: What is the lifespan of Pacific seahorses in the wild? Some researchers say about five years; others think it could be up to 12.
“It will be interesting to see what Roger finds out,” Vincent says.
In June 2017, about one year after Hanson began formally tracking the seahorses, he took on a partner: a young scuba instructor named Ashley Arnold.
Arnold, who has short red hair and a jocular vibe, is a former Army staff sergeant who served in Iraq and Afghanistan. She learned to dive as part of a program the Salt Lake City Veterans Affairs hospital offered to female veterans suffering from post-traumatic stress disorder and military sexual trauma. Arnold suffered from both. Diving became her salvation.
Dive instructor Ashley Arnold is a former Army staff sergeant who says that diving at least twice a week helps her deal with PTSD and MST.
(Carolyn Cole / Los Angeles Times)
“All the irritation on the surface disappears when you go under the water,” she says. “It’s like, ‘What was I concerned about?’ You forget about everything else. Nothing else matters.”
She used her GI Bill to pay for a scuba instructor course and to set up her own business. Now, she finds that if she dives at least twice a week and has a dog, she does not need to take medication.
“All the irritation on the surface disappears when you go under the water.”
— Ashley Arnold
“That’s a pretty big statement in my opinion,” she says.
Arnold and Hanson met in June 2016 on a dive trip to Catalina. Hanson mentioned his seahorses. Arnold was intrigued, but still lived in Salt Lake City.
One year later, Arnold moved to Huntington Beach and gave Hanson a call.
“I said, ‘Hey Roger, let’s chat. Any chance I could join you at the seahorses you talked about?’” she says. “And he decided I was acceptable.”
Now, Arnold and her boyfriend, Jake Fitzgerald, check in on the seahorses about once a week and help Roger rebuild the city he created for them.
Rog Hanson, 68, teamed up with dive instructor Ashley Arnold two years ago to keep watch over a small colony of Pacific seahorses.
(Carolyn Cole / Los Angeles Times)
“We call them our kids because we love them so much,” Arnold says.
Hanson and Arnold are very protective of their seahorse family. They tell visitors to remove GPS tags from their photos. They swear them to secrecy.
There is little chance anyone would find Hanson’s seahorses without a guide. Also, diving in these waters off Long Beach can be a challenge.
The water is shallow. It’s hard to get your buoyancy right. A misplaced flipper kick can stir up blinding sand and silt.
But if Hanson wants to show you his underwater world, nothing will stop him. He will hold you firmly by the hand and guide you down to the forest he built at the bottom of the bay.
Ashley Arnold, right, gets rinsed off with a hose by Rog Hanson after a dive Alamitos Bay.
(Carolyn Cole / Los Angeles Times)
He will use a plastic tent stake, jabbing it into the bottom to propel himself — and you holding on — across the ocean floor. When he spots a seahorse he will use the stake as a pointer. Through the murky water you strain to see. Then it appears.
Orange and rigid. Thin snout. Bony plates. Stripes down the torso. Totally still.
And if you’ve never seen a seahorse in the wild before, you will feel honored and awed, as if you’ve just seen a unicorn beneath the sea.
Science
California’s summer COVID wave shows signs of waning. What are the numbers in your community?
There are some encouraging signs that California’s summer COVID wave might be leveling off.
That’s not to say the seasonal spike is in the rearview mirror just yet, however. Coronavirus levels in California’s wastewater remain “very high,” according to the U.S. Centers for Disease Control and Prevention, as they are in much of the country.
But while some COVID indicators are rising in the Golden State, others are starting to fall — a hint that the summer wave may soon start to decline.
Statewide, the rate at which coronavirus lab tests are coming back positive was 11.72% for the week that ended Sept. 6, the highest so far this season, and up from 10.8% the prior week. Still, viral levels in wastewater are significantly lower than during last summer’s peak.
The latest COVID hospital admission rate was 3.9 hospitalizations for every 100,000 residents. That’s a slight decline from 4.14 the prior week. Overall, COVID hospitalizations remain low statewide, particularly compared with earlier surges.
The number of newly admitted COVID hospital patients has declined slightly in Los Angeles County and Santa Clara County, but ticked up slightly up in Orange County. In San Francisco, some doctors believe the summer COVID wave is cresting.
“There are a few more people in the hospitals, but I think it’s less than last summer,” said Dr. Peter Chin-Hong, a UC San Francisco infectious diseases expert. “I feel like we are at a plateau.”
Those who are being hospitalized tend to be older people who didn’t get immunized against COVID within the last year, Chin-Hong said, and some have a secondary infection known as superimposed bacterial pneumonia.
Los Angeles County
In L.A. County, there are hints that COVID activity is either peaking or starting to decline. Viral levels in local wastewater are still rising, but the test positivity rate is declining.
For the week that ended Sept. 6, 12.2% of wastewater samples tested for COVID in the county were positive, down from 15.9% the prior week.
“Many indicators of COVID-19 activity in L.A. County declined in this week’s data,” the L.A. County Department of Public Health told The Times on Friday. “While it’s too early to know if we have passed the summer peak of COVID-19 activity this season, this suggests community transmission is slowing.”
Orange County
In Orange County, “we appear to be in the middle of a wave right now,” said Dr. Christopher Zimmerman, deputy medical director of the county’s Communicable Disease Control Division.
The test positivity rate has plateaued in recent weeks — it was 15.3% for the week that ended Sept. 6, up from 12.9% the prior week, but down from 17.9% the week before that.
COVID is still prompting people to seek urgent medical care, however. Countywide, 2.9% of emergency room visits were for COVID-like illness for the week that ended Sept. 6, the highest level this year, and up from 2.6% for the week that ended Aug. 30.
San Diego County
For the week that ended Sept. 6, 14.1% of coronavirus lab tests in San Diego County were positive for infection. That’s down from 15.5% the prior week, and 16.1% for the week that ended Aug. 23.
Ventura County
COVID is also still sending people to the emergency room in Ventura County. Countywide, 1.73% of ER patients for the week that ended Sept. 12 were there to seek treatment for COVID, up from 1.46% the prior week.
San Francisco
In San Francisco, the test positivity rate was 7.5% for the week that ended Sept. 7, down from 8.4% for the week that ended Aug. 31.
“COVID-19 activity in San Francisco remains elevated, but not as high as the previous summer’s peaks,” the local Department of Public Health said.
Silicon Valley
In Santa Clara County, the coronavirus remains at a “high” level in the sewershed of San José and Palo Alto.
Roughly 1.3% of ER visits for the week that ended Sunday were attributed to COVID in Santa Clara County, down from the prior week’s figure of 2%.
Science
Early adopters of ‘zone zero’ fared better in L.A. County fires, insurance-backed investigation finds
As the Eaton and Palisades fires rapidly jumped between tightly packed houses, the proactive steps some residents took to retrofit their homes with fire-resistant building materials and to clear flammable brush became a significant indicator of a home’s fate.
Early adopters who cleared vegetation and flammable materials within the first five feet of their houses’ walls — in line with draft rules for the state’s hotly debated “zone zero” regulations — fared better than those who didn’t, an on-the-ground investigation from the Insurance Institute for Business and Home Safety published Wednesday found.
Over a week in January, while the fires were still burning, the insurance team inspected more than 250 damaged, destroyed and unscathed homes in Altadena and Pacific Palisades.
On properties where the majority of zone zero land was covered in vegetation and flammable materials, the fires destroyed 27% of homes; On properties with less than a quarter of zone zero covered, only 9% were destroyed.
The Insurance Institute for Business and Home Safety, an independent research nonprofit funded by the insurance industry, performed similar investigations for Colorado’s 2012 Waldo Canyon fire, Hawaii’s 2023 Lahaina fire and California’s Tubbs, Camp and Woolsey fires of 2017 and 2018.
While a handful of recent studies have found homes with sparse vegetation in zone zero were more likely to survive fires, skeptics say it does not yet amount to a scientific consensus.
Travis Longcore, senior associate director and an adjunct professor at the UCLA Institute of the Environment and Sustainability, cautioned that the insurance nonprofit’s results are only exploratory: The team did not analyze whether other factors, such as the age of the homes, were influencing their zone zero analysis, and how the nonprofit characterizes zone zero for its report, he noted, does not exactly mirror California’s draft regulations.
Meanwhile, Michael Gollner, an associate professor of mechanical engineering at UC Berkeley who studies how wildfires destroy and damage homes, noted that the nonprofit’s sample does not perfectly represent the entire burn areas, since the group focused specifically on damaged properties and were constrained by the active firefight.
Nonetheless, the nonprofit’s findings help tie together growing evidence of zone zero’s effectiveness from tests in the lab — aimed at identifying the pathways fire can use to enter a home — with the real-world analyses of which measures protected homes in wildfires, Gollner said.
A recent study from Gollner looking at more than 47,000 structures in five major California fires (which did not include the Eaton and Palisades fires) found that of the properties that removed vegetation from zone zero, 37% survived, compared with 20% that did not.
Once a fire spills from the wildlands into an urban area, homes become the primary fuel. When a home catches fire, it increases the chance nearby homes burn, too. That is especially true when homes are tightly packed.
When looking at California Department of Forestry and Fire Protection data for the entirety of the two fires, the insurance team found that “hardened” homes in Altadena and the Palisades that had noncombustable roofs, fire-resistant siding, double-pane windows and closed eaves survived undamaged at least 66% of the time, if they were at least 20 feet away from other structures.
But when the distance was less than 10 feet, only 45% of the hardened homes escaped with no damage.
“The spacing between structures, it’s the most definitive way to differentiate what survives and what doesn’t,” said Roy Wright, president and chief executive of the Insurance Institute for Business and Home Safety. At the same time, said Wright, “it’s not feasible to change that.”
Looking at steps that residents are more likely to be able to take, the insurance nonprofit found that the best approach is for homeowners to apply however many home hardening and defensible space measures that they can. Each one can shave a few percentage points off the risk of a home burning, and combined, the effect can be significant.
As for zone zero, the insurance team found a number of examples of how vegetation and flammable materials near a home could aid the destruction of a property.
At one home, embers appeared to have ignited some hedges a few feet away from the structure. That heat was enough to shatter a single pane window, creating the perfect opportunity for embers to enter and burn the house from the inside out. It miraculously survived.
At others, embers from the blazes landed on trash and recycling bins close to the houses, sometimes burning holes through the plastic lids and igniting the material inside. In one instance, the fire in the bin spread to a nearby garage door, but the house was spared.
Wooden decks and fences were also common accomplices that helped embers ignite a structure.
California’s current zone zero draft regulations take some of those risks into account. They prohibit wooden fences within the first five feet of a home; the state’s zone zero committee is also considering whether to prohibit virtually all vegetation in the zone or to just limit it (regardless, well-maintained trees are allowed).
On the other hand, the draft regulations do not prohibit keeping trash bins in the zone, which the committee determined would be difficult to enforce. They also do not mandate homeowners replace wooden decks.
The controversy around the draft regulations center around the proposal to remove virtually all healthy vegetation, including shrubs and grasses, from the zone.
Critics argue that, given the financial burden zone zero would place on homeowners, the state should instead focus on measures with lower costs and a significant proven benefit.
“A focus on vegetation is misguided,” said David Lefkowith, president of the Mandeville Canyon Assn.
At its most recent zone zero meeting, the Board of Forestry and Fire Protection directed staff to further research the draft regulations’ affordability.
“As the Board and subcommittee consider which set of options best balance safety, urgency, and public feasibility, we are also shifting our focus to implementation and looking to state leaders to identify resources for delivering on this first-in-the-nation regulation,” Tony Andersen, executive officer of the board, said in a statement. “The need is urgent, but we also want to invest the time necessary to get this right.”
Home hardening and defensible space are just two of many strategies used to protect lives and property. The insurance team suspects that many of the close calls they studied in the field — homes that almost burned but didn’t — ultimately survived thanks to firefighters who stepped in. Wildfire experts also recommend programs to prevent ignitions in the first place and to manage wildlands to prevent intense spread of a fire that does ignite.
For Wright, the report is a reminder of the importance of community. The fate of any individual home is tied to that of those nearby — it takes a whole neighborhood hardening their homes and maintaining their lawns to reach herd immunity protection against fire’s contagious spread.
“When there is collective action, it changes the outcomes,” Wright said. “Wildfire is insidious. It doesn’t stop at the fence line.”
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