NASA Earth Observatory data show that an El Niño-linked drought has left forest cover across Brazil's central and eastern Amazon regions in a dry, combustible state, with fire activity now advancing through those areas. Dry conditions linked to the active El Niño event have spread into the Amazon basin, the result of atmospheric and oceanic shifts that build over many months before their effects reach land.
Rainfall totals across Manaus fell to a fraction of their historical averages during the late-summer months, with NASA-cited data from Brazil's National Institute of Meteorology placing the August shortfall at around 95 percent below the norm and the September gap at roughly 60 percent. Burning activity across woodland areas near Manaus and Santarém stretches outward through Pará and Amazonas states, reaching as far as the Amazon River's mouth.
Thick smoke settled across Manaus — a metropolitan area home to more than two million residents — on October 12, driving fine-particle concentrations to a recorded 135 micrograms per cubic metre. On the morning of October 10, air-quality equipment stationed in Manaus logged concentrations of fine particulate matter near 209 micrograms per cubic metre, while instruments further along in Itacoatiara captured considerably steeper figures. Between 1 and 8 October, health facilities in Manaus logged 82 patient visits classified as smoke-related emergencies.
Thirty-six municipalities across Amazonas state are now operating under a declared fire emergency, with the city of Manaus having shuttered its schools and called off outdoor gatherings, while researchers at NASA indicate the fires are projected to persist through to the onset of the rainy season, expected sometime between December and January. A fire emergency spanning Manaus and its surrounding metropolitan zone, the state's southern reaches, and river communities such as Itacoatiara, Parintins, and Tefé was put in place by Amazonas Governor Roberto Cidade on 10 October. Within a matter of hours, the national government had formally acknowledged the decree, opening a pathway for the state to draw on federal funding.
In Amazonas, the tally of satellite-detected fire hotspots reached 3,726 during September — a count roughly four times greater than the 942 logged across the same month a year earlier. Tallies of this kind remain provisional, with fires obscured beneath smoke or dense forest cover liable to go undetected.
On 12 October, the Aqua satellite's MODIS instrument gathered the smoke imagery that NASA subsequently released. According to NASA data, under 1% of Amazon fires in Brazil trace back to lightning strikes, with the most destructive outbreaks having originated as intentional burns set on agricultural land and pastures before spreading into the forest floor.
Burn tallies for the Santarém region may run roughly 40 percent higher than conventional active-fire monitoring captures, according to findings by Shane Coffield, a University of Maryland researcher conducting work in partnership with NASA Goddard, as reported by NASA. Between 50 and 70 fires burning without containment were counted across that area by the team he led.
Fine-particle smoke poses the steepest health threat to four populations in particular: children, older adults, pregnant individuals, and those living with heart or lung conditions. People in riverside communities where healthcare options are thin face steeper hurdles accessing treatment, and waterway transport — the lifeline many of those towns rely on — can be thrown into disarray by smoke and poor visibility.
Events elsewhere set the sequence in motion. Beginning from August, peat fires and drought conditions across Indonesia pushed smoke across entire island chains, while media reports indicated that the resulting haze led authorities to shut schools attended by roughly 2 million students in Malaysia.
Morton, a NASA researcher, noted that the Amazon appears to be following a trajectory already traced by Indonesian fire activity — positioning the region as the next point in a sequential pattern that climate records from the 2015–16 El Niño period, and again from 2023, have documented before. Morton noted that those woodland areas had already experienced fires in both 2015 and 2023, and that trees left partially damaged — yet still standing — after each of those events tend to add to the overall fire load of whatever canopy remains.
In a NASA report, Morton called on residents across the area to refrain from any burning whatsoever during the current season, describing it as a period when avoiding such activity entirely was the advisable course of action. State and federal firefighting crews have been put to work under official direction, with Ibama's figures pointing to upwards of 200 blazes brought under control since the current burning period got under way.
Fires burning through tropical forests push stored carbon back into the atmosphere, a dynamic that places such events under close watch by researchers compiling worldwide climate records. Roraima, northern Pará, Amapá, and stretches of Venezuela, Guyana, and Suriname are forecast by NASA to face additional waves of fire activity, while the southern Brazilian Amazon and Paraguay are projected to see their peak period of drought and fire risk arrive sometime in August or September of 2027.
Wet-season rainfall typically brings an end to Brazil's annual burn cycle, and NASA's modelling points to the Manaus and Santarém areas seeing that shift arrive sometime between December and January.
