Revisiting the LA fires

Researchers in South Dakota State University's Geospatial Sciences Center of Excellence utilized satellite data to better understand how destructive wildfires swept through Los Angeles in January 2025. 

A severe drought, powerful Santa Ana winds and a not-fully-extinguished brushfire combined to create the most destructive wildfire in the history of Los Angeles in early 2025. The Palisades Fire, which fully ignited on Jan. 7, destroyed Los Angeles' Pacific Palisades neighborhood, killing 12 people and burning 6,800 homes and buildings.

A second wildfire, the Eaton Fire, burned simultaneously in the Los Angeles area and was equally destructive. This fire, which also began on Jan. 7, killed 19 people and destroyed 9,000 buildings in the Altadena community.

Combined, the 2025 LA wildfires are considered the second deadliest and destructive in state history, trailing only the 2018 Camp Fire in Northern California.

The deadly, destructive and extreme nature of these wildfires have prompted researchers to reexamine what happened. What characteristics made this fire so deadly? How did it spread so quickly? What can we learn from this disaster to improve evacuations and prevent future deaths?

A joint project from South Dakota State University's Geospatial Sciences Center of Excellence, the University of Maryland's Center for Environmental Science, and the National Oceanic and Atmospheric Administration Center for Satellite Applications and Research has leveraged fire and emission observations from multiple satellites to address these key questions. 

"Using satellite images, we investigated how fast the fires spread, how intensely they burned, and how much smoke pollutants they released," said Fangjun Li, assistant research professor at SDSU and a lead author on the study.

The fires were so destructive and dangerous because of how quickly they spread after ignition. According to the team's findings, both the Palisades and Eaton fires burned nearly 80% of their total area within the first 24 hours. The Santa Ana winds, which reached speeds of 90 miles an hour, made the fires extremely difficult to contain.

"These wildfires, driven by hurricane-like winds, spread at a pace that far outstrips traditional planning timelines, leaving limited time for safe evacuation and firefighting response," said Xiaoyang Zhang, SDSU Distinguished Professor and co-director of the Geospatial Sciences Center of Excellence.

The Palisades Fire was first reported at 10:30 a.m. on Jan. 7. By 3 p.m., the fire had grown rapidly to cover over 1,200 aces. Spreading at a maximum rate of 2.3 miles per hour, the fire destroyed nearly the entire Pacific Palisades neighborhood in just five hours. The rate at which the fire spread created an extremely hectic evacuation situation. Many roads became gridlocked, and people had to abandon their cars to escape the flames.

"Fast-moving flames and heavy smoke under extreme wind conditions can also seriously impair visibility, hinder traffic and limit firefighting efforts on the ground and from the air," Zhang said.

The intensity in which the fires burned were also of interest to the researchers. Interestingly, the Palisades Fire burned more intensely at night and were stronger than natural vegetation fires. During the day, the situation reversed, the researchers found. The daytime residential fire was less intense than daytime forest fires. The hillside neighborhoods, temperatures and the amount of "live fuel" available — like landscaping and wood fences — all played a role in the spread and intensity of the fires.

"Fire intensities in residential areas were markedly high," Li noted.

By fusing data from different satellites, the researchers were able to reconstruct the wildfires and gain valuable insights into their spread and intensity. The remote sensing tools the researchers utilized may help in improving future evacuation planning and firefighting operations.

"For destructive wildfires in or near the residential areas, timely information on fire extent, spread rate and direction, intensity and smoke emissions at intervals of a few minutes to one hour is critical for safe evacuation, firefighting operations, utility management and downwind air quality advisories," Li said.

Improving evacuations will be critical for states like California as wildfires have become more destructive and severe in the last few decades. Between 1972 and 2018, the number of acres burned each year has increased by a factor of four while the average area of forests burned each summer has grown by nearly eightfold. Property destruction has reached nearly $1 billion annually as a result, and that number is expected to increase in the future.

The results of this work underline the need for early and coordinated evacuation planning, especially in residential areas prone to wildfires.

The study, titled "Fire Spread, Intensity and Emissions Observations by Multiple Satellites: The Southern California Wildfires of January 2025," was published in the journal AGU Advances in February 2026. Contributing authors include Maryland's Mark Cochrane and Shobha Kondragunta as well as SDSU's Shuai An.

Funding for this research was provided by the National Oceanic and Atmospheric Administration and the National Aeronautics and Space Administration.