A dangerous wave of wildfires is spreading rapidly across the tropics, and the Amazon rainforest is now facing a growing crisis. Fueled by a severe drought linked to the El Niño climate phenomenon, aggressive fires are sweeping through parts of Brazil, filling major cities with toxic smoke and threatening fragile ecosystems that have already been severely damaged by previous fire seasons.
Unlike fast-moving natural disasters like tornadoes or severe thunderstorms, which can cause widespread destruction in a matter of minutes, El Niño influences global weather patterns over many months. The powerful climate phenomenon can severely disrupt rainfall across vast regions, creating unusually dry conditions that allow runaway fires to spread at an alarming rate. Scientists are now warning that the Amazon rainforest may only be entering the beginning of a prolonged, highly destructive fire season that could stretch well into next year.
NASA Satellites Detect Surging Amazon Wildfires
Beginning in September 2026, high-resolution satellite observations revealed a sharp, troubling increase in active fires and smoke emissions across both the central and eastern portions of the Amazon basin. This growing environmental activity was quickly identified and tracked by several sophisticated monitoring systems, including NASA’s Fire Information for Resource Management System (FIRMS), the Global Fire Emissions Database (GFED), and NASA Worldview imagery.
The heavily affected geographic area extends outward from the dense forests surrounding Manaus and Santarém—two major commercial, economic, and transportation hubs in Brazil—stretching eastward toward the vast mouth of the Amazon River.
On October 12, 2026, the MODIS (Moderate Resolution Imaging Spectroradiometer) instrument aboard NASA’s Aqua satellite captured a striking, high-resolution image showing enormous, billowing plumes of smoke rising from aggressive fires burning on both sides of the Amazon River.
At the time these images were captured, thick, hazardous smoke had completely engulfed Manaus, the sprawling capital of Brazil’s Amazonas state. City officials reported dangerously polluted air, with concentrations of fine particulate matter—known as PM2.5—exceeding 135 micrograms per cubic meter. These microscopic particles can easily penetrate deep into human lungs, posing severe, immediate health risks to vulnerable populations. These alarming measurements placed the city’s air quality into the second-worst category of the regional air quality index.
The heavy smoke brought major economic and social disruptions to Manaus, a metropolitan hub that is home to more than 2 million people. Local authorities took swift action as air quality deteriorated, ordering the temporary closure of schools, the cancellation of public events, and the suspension of children’s sports leagues while issuing urgent warnings for residents to remain indoors and avoid outdoor physical activity.
El Niño Is Triggering a Wildfire Domino Effect
According to Douglas Morton, an accomplished Earth system scientist at NASA’s Goddard Space Flight Center, the intensifying fires surrounding Manaus and Santarém are not isolated incidents; rather, they are part of a much larger, interconnected global pattern.
Morton describes the meteorological phenomenon as a devastating "cascade" of tropical fires driven by regional rainfall disruptions directly associated with El Niño. The destructive sequence typically begins near the equator in Southeast Asia, where prolonged drought helps ignite massive peat fires in Indonesia. These subterranean fires burn deep through carbon-rich organic material stored in the soil. As dry, high-pressure conditions subsequently develop elsewhere around the globe, fire activity rapidly intensifies in other vulnerable tropical zones, including the central and eastern Amazon.
This overarching pattern is far from unprecedented. Following the devastating 2015-2016 El Niño event, Morton worked closely with climate researchers from the University of California, Irvine; Vrije Universiteit Amsterdam; and the University of Maryland to examine how tropical wildfires followed shifting global rainfall patterns. Their critical findings were published in a comprehensive 2017 scientific study. Researchers later observed a strikingly similar catastrophic sequence during the El Niño event of 2023.
Now, the unfolding 2026 El Niño is once again producing the exact same dangerous progression across the globe.
Indonesia has already experienced months of relentless drought, heavy smoke, and destructive fires beginning as early as August. Throughout October, intense wildfires destroyed hundreds of residential homes, while dense, choking smoke blanketed entire islands on most days of the week.
"Now, in the Amazon, we’re seeing the second domino in the cascade fall," Morton said, referring to the rapidly increasing number of uncontrolled fires burning through the Brazilian states of Pará and Amazonas.
Scientists Warn More Fires Could Spread Into 2027
The current surge of destruction may represent only a single stage of a much longer, multi-month fire season.
Morton and his collaborative team of researchers anticipate that active fire conditions will continue to expand northward throughout November and December 2026. The specific geographic regions currently at risk include the Brazilian states of Roraima and Amapá, northern portions of Pará, and neighboring territories in Venezuela, Guyana, and Suriname.
Following this northward expansion, the dangerous weather pattern is expected to shift back toward the south. By August and September 2027, severe drought conditions and heightened wildfire danger could reach their absolute peak in the southern Amazon regions of Brazil, as well as neighboring Paraguay.
One of the most troubling aspects of the current environmental crisis is that a significant portion of the threatened rainforest has burned during previous climate events.
"It’s so striking — and frustrating — that this is happening all over again," Morton said, pointing out that tropical forests heavily affected by the intense fires of the 2015 and 2023 El Niño events are once again catching fire and burning.
Wildfires are exceptionally destructive in tropical rainforest ecosystems because the vast majority of native plants and animals living there simply have not evolved to withstand frequent burning. Unlike other global ecosystems where fire is a regular, natural part of the environmental lifecycle, Amazon forests can suffer severe, prolonged, and sometimes irreversible damage when destructive flames move through their canopies and understories.
Previous fires have also left vast parts of the forest significantly more vulnerable to future destruction. Trees that were only partially burned or stressed during earlier events remain weakened, making the remaining vegetation far more susceptible to catching fire again. Morton warned that some of the active blazes could therefore burn with far greater intensity than previous generations of fires.
He expects the aggressive fires near Manaus and Santarém to persist unabated until regional seasonal rains finally return, which is historically expected around December 2026 or January 2027.
However, local communities located in regions farther north and south still have a narrow window of opportunity to reduce the imminent danger before local weather conditions deteriorate further.
"Given the intensity of this El Niño, this really is the year for people to avoid burning at all costs," Morton emphasized.
Extreme Drought Turns Human-Started Fires Into Wildfires
Although the Amazon basin is experiencing a historic fire emergency, lightning is exceedingly rare as a primary ignition source for fires in Brazil’s dense rainforest.
The region is normally characterized by high humidity and heavy moisture, meaning that natural lightning strikes account for less than 1 percent of all fires, according to Morton. This scientific reality means that virtually every single fire currently spreading through the Brazilian Amazon originated directly from human activity.
What makes the year 2026 particularly dangerous, however, is the unprecedented severity of the ongoing regional drought.
Data from Brazil’s National Institute of Meteorology revealed that total rainfall in Manaus was a staggering 95 percent below normal levels in August, followed by precipitation levels 60 percent below normal in September.
These extremely dry, parched conditions have effectively transformed localized fires that might otherwise have remained safely confined to managed agricultural areas into fast-moving, uncontrolled wildfires.
Morton explained that many of the larger blazes currently ravaging the landscape began as deliberately set agricultural fires used for routine land management. These common practices include removing woody shrubs from cattle grazing land or clearing stubborn crop residue from harvested fields. Once the initial flames escaped human control, they rapidly spread into the rainforest’s parched understory—the fragile layer of dense vegetation growing directly beneath the towering canopy trees.
Advanced satellite analysis suggests that approximately 50 to 70 uncontrolled fires are currently burning through the landscape in the Santarém area alone, according to Shane Coffield, an assistant research scientist at the University of Maryland who conducts research at NASA Goddard.
NASA Uncovers Hidden Fires That Satellites Are Missing
Despite the advanced capabilities of modern space-based observation, the actual number of active Amazon wildfires may be substantially higher than standard, publicly available satellite monitoring systems currently indicate.
As part of an ongoing NASA Earth Action project, Coffield is closely studying high-resolution observations collected by VIIRS (Visible Infrared Imaging Radiometer Suite), a state-of-the-art satellite instrument specifically engineered to detect thermal heat signatures associated with active fires on the Earth’s surface.
His primary scientific goal is to identify hidden fires that routinely fail to meet the strict detection thresholds required in official FIRMS data products.
These crucial additional detections, categorized by researchers as "candidate fires," could ultimately help scientists develop a much more complete and accurate picture of true wildfire activity across the basin. Coffield plans to directly provide the precise locations of these hidden blazes to MapBiomas, a collaborative, multi-institutional network of universities, non-governmental organizations, and technology companies dedicated to tracking fires and land-use changes throughout the Amazon.
Initial research findings strongly suggest that conventional monitoring methods are overlooking a significant percentage of active blazes.
"For the area around Santarém, we’ve identified about 40 percent more fires than you’ll see in active fire counts from FIRMS," Coffield stated.
Detecting underground or understory fires burning beneath a thick rainforest canopy remains an extraordinary scientific challenge, even for the most sophisticated instruments currently in orbit. Satellite sensors primarily identify wildfires by measuring thermal infrared radiation, which reveals the heat generated by burning organic vegetation below.
However, thick regional smoke, persistent cloud cover, and dense tree canopies can severely interfere with those orbital measurements. Fires that burn slowly and creep through the damp understory are particularly difficult to detect because the thick vegetation towering above them effectively conceals their thermal heat signatures from space.
Consequently, official satellite fire counts can occasionally plummet even while extensive burning continues unabated on the ground below.
"On some of the smokiest days, we have very few detections from MODIS and VIIRS, and we know that isn’t right," Coffield noted.
By successfully identifying hidden fires that existing monitoring systems consistently overlook, NASA researchers hope to provide scientists, policymakers, and local land managers with a far more accurate understanding of the unprecedented threats facing the Amazon rainforest as the severe El Niño-driven fire season continues to unfold.
