Californians are no strangers to wildfires, a natural phenomenon that typically peaks during the hot, dry, and windy period of late summer, marking a predictable fire season. Since the mid-2000s, however, wildfire effects have grown in scale and frequency, extending beyond expected fire season lengths and burning unprecedented acreage in California and worldwide. These fires impact the natural environment and increasing numbers of people, threatening lives, property, communities, air quality, and vital infrastructure such as water, power, and natural resources. Without effective strategies to better understand, predict, and manage future fires, these impacts will continue to worsen.
Public awareness of wildfire risks surged in 2020 when a rare summer lightning event sparked thousands of fires in California. Five enormous and complex fires merged and burned for several weeks, consuming nearly 17,000 square kilometers (km2). The August Complex fire, largest in California’s history and its first “gigafire” (burning more than 4,000 km2), burned almost 1 percent of the state’s land. The later Tubbs, Camp, and Palisades fires continued the trend of larger, more numerous, and more intense fires, becoming some of the deadliest and most destructive in the state’s history. This global trend is evident elsewhere in the 2019 to 2020 Black Summer Bushfires in Australia that burned more than 170,000 km2 of land and killed an estimated 1 billion animals with smoke observed as far away as South America.
Wildfires are affecting the Department of Energy (DOE), National Nuclear Security Administration (NNSA), and related infrastructure as well. The 2024 Windy Deuce fire in the Texas panhandle spread quickly to within eight miles of the NNSA’s Pantex nuclear facility. Limited resources to quickly predict how the fire would advance resulted in suboptimal evacuation guidance and placed personnel at increased risk. The 2022 Cerro Pelado fire in New Mexico burned within five miles of Los Alamos National Laboratory and led to a site closure. “The impacts of wildfires on people and DOE infrastructure are our alarm bells that we need better tools to understand how wildfires can affect the national laboratories, other DOE facilities, or facilities in which DOE is interested,” says Donald Lucas, a staff scientist in Livermore’s Atmospheric, Earth, and Energy Division (AEED). On top of these national security problems that wildfires pose, Livermore’s location in California’s fire-prone San Francisco East Bay Area gives the Laboratory a vested interest in wildfire research to manage and minimize losses and to improve predictive capabilities, risk assessment, and preventative measures before fires can spread.
A Wicked Problem
Myriad factors have contributed to the increased frequency, intensification, size, and duration of wildfires over the years. Forest management and changes in the natural environment are two factors that reinforce each other. For example, warmer temperatures lead to more evaporation, causing drier vegetation and soils. In addition, precipitation patterns have shifted, causing rainfall to occur in fewer, heavier storms with longer dry periods between them. Winters are also warmer, allowing pests, such as bark beetles, to survive in greater numbers. These changes result in stressed trees that are more vulnerable to beetle infestations. Forest management practices, such as maintaining high tree density through logging (removing only the largest, most fire-resistant trees) and fire suppression, increase competition for reduced or increasingly intermittent moisture. Dense forests trap more snow in tree branches, causing the snow to sublimate into the air rather than soak into the soil. At the same time, historic logging practices and fire suppression have allowed dry, flammable materials to build up. When fires do occur, the accumulated fuels help the fires spread quickly, intensify, and reach the tree crowns.
This confluence of factors impacting forest health and leading to an increase in dry fuel contributes to wildfires at unforeseen intensities and frequencies, making already unpredictable natural and human-caused disasters more challenging to fight. “We’ve developed significant experience and knowledge fighting fires over the decades. However, new fires are behaving differently from old fires, and the prior heuristics—rules of thumb—are no longer useful,” says Jeffrey Mirocha, an AEED staff scientist. “Fires are growing more explosively and moving more quickly, and with that comes a different risk profile that we need new tools to understand.”
The complicated and interconnected causes of more destructive wildfires require solutions of similar complexity in thought and research. “No single approach to understanding cause and effect, risk, or impacts will solve the issue, so we’re seeing a greater variety in the tools that researchers are bringing to bear on this problem,” says Lucas. According to Mirocha, wildfires are considered a “wicked problem,” one that has no simple solution or central authority and that changes over time. To tackle the issue of wildfires requires multifaceted efforts that take into consideration their various causes and effects. Toward this end, Livermore has funded several projects to research possible responses to this wicked challenge.
Firefighting on Many Fronts
A wide breadth of research approaches has provided useful insights into a greater understanding of wildfires. These approaches include statistical analysis to help predict areas that will be most affected, AI and machine learning to improve modeling capabilities, chemical kinetics modeling to improve fire combustion and emissions characteristics, and atmospheric science to explore the coupling between fire and the atmosphere, as well as to explore implications of wildfire smoke at local, regional, and global scales. From 2019 to 2022, Mirocha led a project funded through the Laboratory Directed Research and Development (LDRD) Program to improve wildfire simulation capabilities with the WRF-SFIRE model, a simulation code that couples the Weather Research and Forecasting (WRF) atmospheric model with a surface fire spread and emissions model (SFIRE). A key result of this work was the identification of pathways to improve the representation of fuel consumption as well as heat and emissions releases from the fire spread model.
Building on this first project, Livermore staff scientist Chiara Saggese led an LDRD project that applied chemical combustion models designed for fossil fuel applications to different firewood fuel scenarios, providing information about heat release, rate of fuel consumption, leftover fuel, and emissions. Different moisture contents, temperatures, and types of fuel source impact how wood burns. By exploring these factors, Saggese created improved parameters for fire spread models such as the Rothermel model—a foundational surface fire spread model for many fire modeling systems, including WRF-SFIRE—which will in turn improve the resulting simulations of wildfire spread, heat release, and emissions. Qi Tang, a Livermore atmospheric scientist, scaled up this work in another LDRD project that examined the global effects of large fire emissions. Wildfires create aerosol particles, which, in addition to their well-known adverse human health impacts when inhaled, can also penetrate the stratosphere above and remain suspended for years. Suspended aerosols interfere with chemical processes and interact with both solar and infrared radiation, driving global responses far from and long after the original fire. A better understanding of aerosols’ tendencies and interactions with clouds and radiation can offer insights into fires’ potential impacts. “To have someone focused on fuel and combustion, someone else looking at the local, regional scale implications, and then a third person looking at the global scale really demonstrates how multifaceted the research and development space is for the topic of fires,” says Lucas.
To broaden the reach of Livermore’s research, collaborations within the Laboratory and beyond are paving the way for practical applications. Fire researchers are incorporating capabilities from the National Atmospheric Release Advisory Center (NARAC), the onsite resource center that performs real-time assessment of atmospheric releases, to link fundamental research with NARAC’s facilities for rapid response in a two-way pipeline. NARAC’s push-button forecasts and rapid simulations of plumes offer insight into improving fire forecasting tools to the benefit of firefighters on the ground, while longer-term research techniques provide parameterization capabilities for NARAC to use efficiently when time is too scarce to use a complex physics model.
In addition, Lucas led an Institutional Scientific Capability Portfolio (ISCP) project that developed practical applications based on research outcomes from Mirocha’s LDRD project. Lucas’s project worked with FireGuard, a U.S. National Guard–run effort that provides around-the-clock information to local firefighters about large wildfires—specifically through polygons of active fires that outline where fires are located. These polygons have historically been hand drawn based on multiple environmental data streams, but as new ignitions grow more frequent and lead to more intense wildfires, data management has become a growing challenge. To streamline, Lucas and the team developed tools to automate the construction of polygons so that FireGuard can handle higher volumes of data and keep up with alert creation amid growing needs.
Finally, collaborations with national laboratories and academic partners in the California State University system and the University of California (UC) have facilitated multidisciplinary investigations of some of the deep complexities of wildfires in California. Between 2021 and 2023, Lucas and Mirocha led research components exploring the mitigation of wildfires and their air pollution impacts, respectively, under the UC Lab Fees Research Program, which supports research collaboration between UC faculty and national laboratory scientists. Lucas’s project resulted in a highly cited paper and a new, high-resolution dataset of historical weather over California for wildfire applications. Taking the economy and energy grid into account, such collaborative projects—with the first led by UC Santa Barbara and including UC Berkeley, UC San Diego, and Lawrence Berkeley National Laboratory, and the other led by UC Davis and including UC Berkeley, UC Irvine, UC Merced, and Los Alamos National Laboratory—bring together California’s resources in pursuit of solutions.
A Brighter Future
A combination of new computational tools and better integration among stakeholders is required to face the challenges that current and future fire regimes pose. While WRF-SFIRE contains demonstrated physics capabilities and has worked well on legacy high-performance computing (HPC) architectures, meeting emerging challenges will require new platforms that can effectively run on the next generation of HPC assets. Prior Livermore research has identified the underlying physical and computational requirements to accelerate WRF-SFIRE’s capabilities within a faster and more modern computational platform. Under development through DOE and Livermore’s LDRD program, the Energy Research and Forecasting (ERF) model is a new exascale-oriented, accelerated atmospheric simulation software that implements WRF’s capabilities on modern HPC architectures that runs tens to hundreds of times faster. Adding fire physics to ERF would improve its capacity to meet many of the more pressing fire simulation and prediction challenges.
Historically, research to tackle the many facets of this wildfire problem has been piecemeal, and a unified front for wildfire research does not currently exist. Rather, several different agencies, from the U.S. National Guard to the U.S. Forest Service to federal agencies in charge of agriculture, defense, and energy activities address wildfires on an independent basis. Livermore’s connection to other DOE laboratories, resources from NARAC, and budding collaboration with FireGuard and other institutions further its research capabilities, but the national and global effects of wildfires are increasing. Greater interagency collaboration, or even a formal interagency body, could enhance future efforts and improve their impact. “We operate in a fractured field. If consolidated efforts across agencies occurred, we could see many benefits including reducing costs and ensuring that we aren’t duplicating efforts,” says Lucas. Mirocha adds, “Without coordination, we aren’t sure if we are prioritizing research in the highest impact area or addressing a problem in a way that makes another part of the problem worse.”
AI offers further room for improvement in prioritizing efforts to the most productive and impactful solutions. “My crystal ball ideally would say that, in the future, we can use AI tools to optimize our strategies for working through this wicked problem,” says Mirocha. “I’d like AI to tell us what data we need the most and what our options are for moving forward. Humanity has a hard time when confronted with these complicated issues, but we must move forward and with urgency.”
—Lilly Ackerman
For further information contact Donald Lucas (925) 422-1463 (lucas26 [at] llnl.gov (lucas26[at]llnl[dot]gov)) or Jeffrey Mirocha (925) 422-4627 (mirocha2 [at] llnl.gov (mirocha2[at]llnl[dot]gov)).
