There’s a hard math behind the Los Angeles-area firestorm: When a two-story house is on fire under normal circumstances, three engines and a minimum of 16 crew members are generally dispatched. But as Pacific Palisades homes began to catch fire on Jan. 7, “there were probably at least, within the first two hours, 100 structures fully involved,” said Jack Cohen, a research scientist who spent decades studying fire dynamics with the U.S. Forest Service. “You can’t dispatch and organize enough engines to keep up,” he said — let alone fit that many vehicles on the region’s narrow, hillside roads. In other words, when 70 mph winds are raining embers into suburban communities so achingly vulnerable to fire, extreme blazes are an inevitability that no number of firefighters can control. What begins as wildfire becomes an urban conflagration, with homes serving as the main fuel. To Cohen, the finger-pointing that has ensued since the deadly fires broke out in Southern California — amid reports that hydrants ran dry, a reservoir was empty and extra firefighters were not positioned where fires erupted — is “nonsense.” “The latest dribble with regard to too few crews, too little water, pre-positioning — what crock. None of that is relevant. None of that would have made an ounce of difference in the results,” he said. A dozen experts — top fire officials, academic researchers, conservation advocates and scientists — told NBC News that instead, Southern California and other vulnerable areas need a transformational shift in mindset away from heavy reliance on firefighters to control blazes, and toward an understanding that vulnerable homes are themselves the primary fuel for these kinds of fires. A satellite view of the Palisades fire in the Santa Monica mountains on Jan. 10. (Maxar) “Once the initial ignition comes into a community, the homes become the ignition source and you’re totally in a whack-a-mole situation,” said Dave Calkin, a research forester at Rocky Mountain Research Station in Missoula, Montana. “It’s not a forest management problem. It’s really almost not a wildfire suppression problem. It’s a community design problem, and thinking about the amount of work to retrofit these communities is really staggering.” For decades, people across the American West have been contending with the problem of how to stop wildland fires from entering small towns and suburban neighborhoods — including the hillsides around the nation’s second-biggest city. But going forward, the experts said, the primary hope of preventing a similar disaster is to overhaul communities in fire-prone areas by restricting development and investing billions into retrofits to make them more resilient to fire. When people see a wildfire’s destruction — the charred rubble and pools of melted aluminum from car wheels — they often assume the fire ignited in shrubbery, then barreled toward a neighborhood as a wave of flame, hitting houses like a “tsunami of superheated gas,” Cohen said. But that’s not how it works. Instead, in conditions like those the greater Los Angeles area experienced on Jan. 7, wildfires tend to ignite in grass or shrubs, spewing embers across highways and fuel breaks. Some embers race away on the wind and find their way into vulnerable nooks and crannies in a home, such as open vents, palm tree bark or a broom left on the front porch. The home ignites, becoming the fire’s fuel. Soon, it puts off radiant heat that can ignite the exterior of the home next door, which then allows fire to penetrate to the neighbor’s carpets, furniture and appliances. In dense neighborhoods, the events play out like a contagion. A person tries to hose down embers in Pacific Palisades on Jan. 7. (Etienne Laurent / AP file) “It starts scattered and then burns what’s next to it, ignites and burns what’s next to it, over hours after there is no wildfire influence,” Cohen said. Those flames, all the while, spit embers into strong winds and toward communities miles away. Often, these fires leave behind evidence that the houses themselves fueled the flames: trees, singed, but standing, around the burnt-out shell of a home. Over the past 50 years, California’s population has doubled to 40 million residents, pushing development deeper into fire-prone wildlands. “Ninety-five percent of fires are sparked by people,” said California state Fire Marshal Daniel Berlant, referring to blazes sparked by cigarettes, campfires, powerlines, fireworks, vehicles and other sources. “So, when you add more people into these natural areas, you’re going to see more ignitions.” At the same time, climate change and the associated whiplash between extreme wet and dry seasons is raising the probability that fearsome seasonal winds will overlap with hot, dry conditions. Since the 1970s, California’s fire season has gotten longer by an average of 75 days per year, according to a study from the University of California, Merced. Fifteen of the 20 most destructive fires in the state’s recorded history occurred in the past decade. To address the rising threat, California has invested heavily in wildland firefighting capabilities. Since 2019, the state has put more than $2.5 billion into land management, equipment purchases and additional personnel, among other measures. The number of state firefighters has increased from 5,800 to nearly 10,800, and more than 2,200 treatment projects — including forest thinning, prescribed burns, fuel breaks and other land work — have been completed across 700,000 acres. Such measures can work for moderate and even severe fires, Calkin said, but in extreme fires, they’re unreliable and often “overwhelmed.” A firefighter battles the Palisades Fire along Pacific Coast Highway in Los Angeles on Jan. 8. (Apu Gomes / Getty Images file) In the days ahead of the recent blazes, state, federal and local fire officials ramped up staffing and firefighting preparations, according to Wade Crowfoot, California’s natural resources secretary. Although not all aspects of the fire response may have been perfect, he said “there is no big blind spot that led to the magnitude of destruction that we’re seeing.” Cohen agreed: Southern California, he said, has “the largest response capability in the galaxy, and they still can’t keep up.” Given that the primary factor people can reliably control is how resistant houses are to igniting, wildfire mitigation policy in California is inextricably linked to housing policy — which is mired in a decadeslong crisis of availability and affordability. Fire experts and conservationists say development should either be stopped in fire-prone areas or better designed: Neighborhoods should be constructed with fire-resistant materials and roads made wide enough for people to escape and emergency responders to get in. Existing housing should be retrofitted and hardened with the expectation it will face fire. “All the science is telling us that we need to avoid putting more people into high fire-prone areas because it increases ignition risks,” said Tiffany Yap, a senior scientist with the Center for Biological Diversity. Yap co-authored a report in 2021 that found more than 2 million homes in California are in high-fire-risk areas. State lawmakers, who are grappling with fire risk alongside a dire need for housing, have not restricted development in high-risk zones. Los Angeles County in 2019 approved the construction of a 57,000-person community called Centennial about 65 miles north of downtown Los Angeles — in an area that includes lands classified as a “high” and “very high” hazard fire zone. “The Legislature has struggled coming up with a broad approach to new development in fire zones. There’s a lot of push and pull,” said Scott Wiener, a Democratic state senator from San Francisco. “It’s very contentious. We’ve never been able to put together the coalition to get that done. Perhaps this disaster will allow that coalition to come together.” Five years ago, a bill that would have prohibited new development in high-hazard fire zones stalled after opposition from developers and business interests. The same year, California lawmakers passed a bill that would have required local governments to adopt retrofitting programs for existing communities in fire risk zones and restricted the scale of new developments in certain areas based on wildfire risk. But Newsom refused to sign it, suggesting it would have created inconsistencies and loopholes while placing cost burdens on the state. Flames from the Palisades Fire descend along a road in Pacific Palisades on Jan. 7. (Ethan Swope / AP file) One change California has made: In 2008, it strengthened building codes for the design and materials used in new construction in high-hazard zones. “The challenge is, most homes have not been built in the last 20 years,” said Crowfoot, who co-chairs an interagency wildfire task force created by Newsom. “These are legacy homes that have to be hardened.” California has devoted at least $50 million to home hardening projects since 2020 and launched a small pilot program offering subsidies and financial incentives for homeowners to retrofit. But that program “is not at scale, obviously, to address what occurred in L.A. County or elsewhere,” said Kimiko Barrett, a research and policy analyst at Headwater Economics, a nonprofit research group. Even meeting the highest fire safety standards doesn’t eliminate fire risks, said J.P. Rose, an attorney for the Center for Biological Diversity. During California’s deadliest fire on record — the Camp Fire in Paradise that killed 85 people in 2018 — some homes built to the new codes “still burned to the ground,” Rose said. Indeed, only around 43% of homes in the Paradise area built after 2008 survived the fire, though that was a better outcome than among older houses. About 86% of homes destroyed in Paradise were built before 1990, according to a study in Fire Ecology. “Building codes alone are not going to protect us if we continue building deeper into the fire zones,” Rose said. “The problems of today were created many years ago when officials approved large-scale development in high-risk areas without adequate safeguards.” Fire crews douse houses that caught fire along Pacific Coast Highway in Malibu, Calif., on Jan. 8. (Juan Carlo / USA Today Network file) On the federal level, no agency has invested significant funding in making structures more resilient to wildfire. In 2023, a federal wildfire commission report said it would likely take “tens to hundreds” of billions of dollars each year to fully address the wildfire crisis, including much larger investments in resilience projects. Such work, Cohen said, would need to include detailed, time-consuming assessments of the “ignition potential” of each house in fire-prone communities. Just replacing wooden roofs in wildfire-prone areas across the country would cost at least $6 billion, according to a Headwaters economics study. If governments do not take action, insurance companies will likely be the ones primarily pushing people to make pricey retrofits, under the threat of losing coverage. “Homes that are more wildfire-resistant are going to have an easier time getting insurance over the long run,” Wiener said. “The insurance industry in some ways has more power than the government here.” In the short term, the loss of housing stock due to the recent fires will only worsen Southern California’s housing crisis. Newsom and Los Angeles Mayor Karen Bass both have issued orders to cut red tape and allow homeowners to rebuild up to 110% of their homes’ previous footprint. An aerial view of burned homes from the Palisades Fire in Los Angeles on Jan. 9. (Josh Edelson / AFP via Getty Images) But unless neighborhoods like Pacific Palisades are constructed with wildfire in mind, the same outcome should be expected in the future — or worse, said Char Miller, a professor of environmental analysis and history at Pomona College. He compared the situation to a firestorm that barreled through the Oakland hills in Northern California in 1991. In that case, an extinguished grass fire reignited in “Diablo” wind gusts — seasonal winds similar to the Santa Anas in L.A. — and the more than 1,500 firefighters who responded struggled with hydrants that went dry and navigation on steep, narrow roads. The blaze killed 25 people, injured 150 and destroyed more than 3,300 structures. Miller toured the area in 2014, after it was rebuilt. “They have bigger houses on the same lot, with the same trees, with the same brush in the same location, with cars that are bigger,” Miller said. “No fire truck could come up if a big Suburban was coming down. … We’ve built bigger, but we didn’t build better.” The firefighters he drove around the hills with, Miller said, offered a final assessment: “It’s going to go again.” This article originally appeared on NBCNews.com. Read more from NBC News: First the fires, now the fight: Flaws in California insurance plan will test L.A. homeowners Before the celebrities and influencers came, Pacific Palisades was a ‘small town’ What we know about the victims killed in the California wildfires