
Flames raged around Los Angeles in the US state of California in January 2025. Multiple forest fires killed over 25 people, destroyed more than 10,000 homes and caused billions of dollars in damage. The extent of the destruction is particularly clear from a bird’s eye view, as in this image from NASA’s AVIRIS-3 instrument from January 11, 2025.
The burned area can be seen in Altadena, a Californian city north of Los Angeles. Charred trees and buildings in developed areas are shown in dark brown, while the burned forest areas, particularly in the Angeles National Forest, appear in shades of orange. This forest fire first broke out on the evening of January 7th in the hills of nearby Eaton Canyon. By 10:30 a.m. the next day, the fire had already grown to an area of more than 40 square kilometers, and at the time of the above photo on January 11th it had already grown to 57 square kilometers. By the morning of January 15, the fire had finally stopped its spread and was 45 percent contained.
NASA’s aerial photographs could now be useful in determining the severity and consequences of this and other fires around Los Angeles, such as the soil erosion associated with them. The AVIRIS-3 optical sensor collects data in 286 bands of the electromagnetic spectrum: from visible violet light with a wavelength of 380 nanometers to short-wave infrared with 2500 nanometers. “This data can also help us understand the chemical composition and toxic nature of the ash in the post-fire environment and how it is redistributed over time by wind and water currents,” explains Michael Falkowski, head of the NASA Wildfire program. This makes it possible, among other things, to estimate the expected effects on air quality and human health.