Fires sweeping through Los Angeles have caused extensive destruction, reducing over 10,000 homes to rubble and claiming at least 27 lives. However, the dangers do not end when the flames are extinguished. Post-wildfire hazards, including toxic chemicals, mudslides, household debris, and dispersed ash, continue to pose significant risks, according to Farshid Vahedifard, professor and Louis Berger Chair of the Civil and Environmental Engineering Department at the School of Engineering.
Credit: CC by SA 4.0 – Grigory Heaton Palisades fire after it was first reported
“While Los Angeles is struggling to contain fires, it also faces the high risk of post-fire ground failures such as debris flows and landslides,” Vahedifard said, referencing a recent incident where a landslide split a house in two. “Wildfires can set off a cascade of events that can cause significant damage to buildings, the natural environment, and people, and they can be deadly. They will happen quickly with the first rain, and that would be another disaster,” he added, citing the 2018 Montecito fire, where debris flows filled homes with mud. “The destruction doesn’t end when the fire is put out.”
Vahedifard’s research focuses on mitigating these risks, including developing models to predict post-fire rainfall-triggered landslides. He collaborates closely with wildfire-prone rural communities in California, where vulnerability is highest. Through surveys and focus group research with emergency managers from nine California counties, he is working to better understand the challenges faced by responders and residents during wildfires and propose strategies for managing their cascading impacts.
Wildfire building codes
Vahedifard highlighted the issue of “fragmented and inconsistent” building codes, which can undermine protection efforts. California’s Chapter 7A of the Building Standards Code provides guidelines for construction in Wildland-Urban Interface (WUI) zones, but these codes are not uniformly applied across all wildfire-prone areas. “Communities outside the designated WUI zones, which are increasingly at risk due to urban sprawl and climate change, often lack mandatory requirements for wildfire-resistant construction,” he said. “Even within WUI-designated areas, enforcement of wildfire-specific codes is inconsistent.”
The ongoing wildfire crisis in Los Angeles underscores the consequences of these gaps. Many homes in high-risk areas lack basic wildfire-resistant features, such as non-combustible roofing, ember-resistant vents, or fire-resistant landscaping. Vahedifard emphasized the need for standardized, nationwide building codes that address fire resilience. “We should use this opportunity to make sure that our building codes are ready to address fire resiliency and redouble efforts to inspect and ensure compliance,” he said.
Advanced risk models
As climate change intensifies the frequency and severity of wildfires, Vahedifard stressed the importance of developing new risk models that incorporate climate projections, ember transport, and urban fire spread. These models could serve as critical tools for policymakers in establishing codes based on reliable risk assessments.
“Collaboration between federal and state agencies, research institutions, and private-sector organizations — such as NOAA, FEMA, the U.S. Forest Service, and state fire and environmental agencies — plays a key role in advancing climate-informed risk assessments,” Vahedifard said. “Universities and research organizations contribute cutting-edge modeling techniques, while insurance companies, urban planners, and emergency management offices are increasingly investing in predictive models to assess long-term fire risks and financial impacts.”
The absence of well-established wildfire risk models has broader implications, particularly in California, where insurers rely on proprietary models to assess risks. This has led to rising premiums or denial of coverage in high-risk areas. “When insurers cannot rely on uniform, evidence-based frameworks to evaluate risk, it leaves homeowners underinsured or uninsured, further deepening the financial and social impacts of wildfires,” Vahedifard explained. “Without reliable risk models, communities will struggle to make decisions about zoning, defensible spaces, and evacuation routes, leaving them ill-prepared for actual wildfire events.”
Proactive use of technology
While risk models for hazards like earthquakes and hurricanes are well-integrated into building codes, wildfire risk modeling remains underdeveloped. Vahedifard pointed to emerging technologies, such as satellite imaging and mapping, which can help visualize and assess geohazards like wildfires, landslides, and flooding before they occur. By analyzing data on land cover changes, drought-induced dryness, or heavy precipitation, planners can better forecast fire risks and improve preparedness.
“Satellite imagery and climate data can be combined to give us a heads-up about what’s coming. “We know that climate and land cover are critical precursors to wildfires. Emerging technologies can enable us to detect trends and alert us to be cautious and proactively prepared.”
Improved communication and coordination
Vahedifard also emphasized the need for better risk communication tools to reach vulnerable populations, including seniors, individuals with disabilities, and non-English-speaking residents. Discussions with emergency responders revealed that unclear roles and responsibilities between state and federal agencies often hinder effective wildfire management. “Their concerns included that unclear roles and responsibilities between state and federal agencies hinder response efforts, underscoring the need for better coordination and transparent communication at all levels,” he said.
“The devastation in Los Angeles highlights the urgent need for proactive preparation, as the risks don’t end when the flames are out,” Vahedifard concluded. “Post-wildfire debris flows and landslides can strike quickly with the first heavy rain, causing further destruction. Strengthening predictive models, early warning systems, and mitigation strategies are critical to protecting communities from these cascading hazards.”
