Lessons from the LA Wildfires
The fires in Los Angeles are still burning as I write this. The loss of property, the disruption and loss of lives, and the trauma these fires created are horrendous.
Nevertheless, there are lessons we can learn to change fire policies to mitigate (not prevent) such tragedies in the future.
Wildfires are a natural part of many Western landscapes. Extreme weather and climate are responsible for all large blazes. In 2024, I wrote a piece called “It’s the Wind Stupid,” emphasizing how critical wind is to the creation of large, unstoppable wildfires. In LA, Santa Ana winds up to 100 miles per hour, fanned the flames, and cast embers miles ahead of the fire front. In just 24 hours, the Palisades Fire grew more than 15,000 acres. That’s several football fields a minute!
It’s important to note that increases in wind speed are not linear in how they affect fires. They are exponential. A 20-mph wind gust doesn’t double a 10-mph wind; it quadruples it.
Santa Ana winds have been stoking fires for millions of years. The difference is that we now have sprawl and entire cities on the fire pathway. These are urban fires ignited by wildfire. Once enough homes are ignited, traditional fire-fighting capacities are overwhelmed.
LESSONS FROM THE FIRES
An important lesson from the LA fires and others is that extreme weather conditions negate fuel reductions. State and federal agencies’ mantra about “reducing fuels” fails to recognize that high winds invalidate the effectiveness of logging, thinning, or prescribed burns. The wind blows embers over, around, and through such “fuel reductions.”
Some of the misguided folks that think fuels are always the problem continue to suggest that if only California had done more ‘prescribed burning” like they assert the Indians did and this could have prevented these blazes. First, tribal burns were fairly localized and did not influence vegetation at the landscape scale. However, the majority of the landscape burning in LA is chaparrel. Burning chaparral is not necessary or effective.
The natural fire regime in chaparral is typically 30-100 years between blazes. Burning it more frequently eradicates chaparrel species from the landscape, and replaces it with even more flammable grasses.
If you have vulnerable structures on the landscape, they will ignite. Embers land in gutters, roofs, and wooden decks or are pushed by high winds through unscreened vents to ignite homes.
The Pacific Ocean was the only “fuel reduction” that prevented the Pacific Palisades’ blaze from continuing westward.
Furthermore, like those in Los Angeles, most acreage charred annually is in non-forested landscapes. The LA fires are burning through chaparral. Over the past few decades, many larger fires have been in grasslands or shrubs, not forests. Indeed, approximately 80% of destroyed buildings in the West were lost in grassland and shrubland fires.
Yet federal and state agencies have continued to emphasize logging forests as if this will safeguard communities, which is delusional under extreme weather conditions but also doesn’t apply to many western landscapes.
In the aftermath of the LA fires, like others, such as the Camp Fire that overran Paradise, California, you frequently see green trees surrounding the foundations of homes that were annihilated. This indicates that the fire front did not move through the area; instead, ember showers ignited homes.
There is an explanation. Most homes are built of wood, drywall, and plastics that are more flammable and burn at lower temperatures than trees. These materials can burn completely, whereas most of a tree, even if burnt, remains as a snag because the boles have higher water content and resist combustion.
Wildfires generate a lot of radiant heat that can ignite a home even if a flame never touches it. Wooden walls can ignite, and materials like vinyl, common in windows, can melt and provide entry for embers into the home.
Once ignited, a burning building generates far more heat than the thermal pulse from wildfire. When you have homes nearby, there is a domino effect whereby one burning structure generates enough heat to ignite adjacent homes. This is why entire blocks can be turned to ashes.
Given that traditional measures like thinning the forest or prescribed burns are ineffective during extreme fire weather (and all large blazes only occur during extreme weather), how can communities protect themselves?
First, land use zoning can limit construction in fire-prone areas where geographical features like canyons and ridges enhance fire spread. As homes spread into the hinterland, power lines knocked down by falling trees or wind events become a major ignition source. Hence, the less sprawl, the less chance there is for such ignitions.
Second, most human ignitions (the majority of all fire starts) occur near roads. Road closures and not building roads into the hinterlands are potential defenses against fire starts.
Third, it’s critical to reduce flammable materials near homes. A wood pile adjacent to a house, a wooden fence, shrubs planted adjacent to the structure are all potential ignition points.
Fourth, working from the home outward reduce the flammability of the home itself. A metal roof or one made of a non-flammable material can withstand burning embers. Windows with vinyl frames easily melt from radiant heat and fall apart, allowing embers to enter the home. Construction with metal, brick, adobe, or other non-flammable materials can sometimes help a home to survive a blaze.
Additional measures, such as installing a rooftop sprinkler system, can save a house. A wet structure won’t burn.
However, even if you take all the right precautions to reduce your home’s flammability, if your neighbor does not, the heat from their burning home can ignite your structures. So, community-wide hazard reduction programs, such as restrictions on burning yard waste or periodic checks to make sure flammable materials are moved away from house foundations.
The wake-up call of the LA fires is the recent announcement that 2024 was the warmest temperature across the planet in thousands of years. With increasing heat, drought, and high winds, we can expect more fires like those southern Californians are experiencing.
