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Formosa do Rio Preto fire, 11 September 2026 Formosa do Rio Preto, Mateiros

Out · last detection 22 Sept 2026, 16:18 UTC

The fire started on 11 September 2026 in Formosa do Rio Preto, Brazil, and satellites saw it burning for 13 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 10,589 hectares from heat detections, spread across 2 municipalities.

It is the 88th largest in Bahia since 2016 (of 467 with a page). Number 109 in Brazil in 2026, of 768.

Compare with…

Suggestions: Mateiros · 2017Formosa do Rio Preto · 2026Mateiros · 2025Formosa do Rio Preto · 2022

Burnt area
10,589ha
GWIS perimeter (Copernicus)
Duration
13days
11 Sept 2026 – 23 Sept 2026
Municipalities hit
2
municipalities
Started on
11 Sept
2026
Heat detections
181
in a single hotspot: 358 MW
Danger at start
52
Extreme · FWI index
Average daily power
314MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 11 Sept23 Sept
22 Sept 2026

How it evolved, day by day

11 Sept 2026 · 331 MW · 7 12 Sept 2026 · 76 MW · 9 13 Sept 2026 · 74 MW · 7 14 Sept 2026 · 868 MW · 11 15 Sept 2026 · 173 MW · 17 16 Sept 2026 · 410 MW · 30 17 Sept 2026 · 137 MW · 26 18 Sept 2026 · 614 MW · 46 19 Sept 2026 · 745 MW · 25 20 Sept 2026 · 10 MW · 2 22 Sept 2026 · 17 MW · 1
11 Sept 13 Sept 14 Sept 15 Sept 17 Sept 19 Sept 22 Sept

Fire radiative power detected each day, in megawatts, and number of hotspots. The magenta bar marks the peak day.

The weather it burned in

38°high
57km/h · peak gust
14%lowest humidity

It had gone 4 days without rain (1 mm or more) when it started. Rain came after the fire: 6.0 mm on 2 Oct.

This area had burned before

51% of the perimeter overlaps earlier fires recorded since 2016: 300 ha in 2016, 2,864 ha in 2017, 122 ha in 2019, 1,925 ha in 2021, 518 ha in 2022, 903 ha in 2023, 36 ha in 2025. Part of it burned more than once, so the yearly figures add up to more than the 5,383 ha that had burned before.

How big is it?

10 km
It burned the equivalent of 6.7% of the area of London (106 km² against 1,583 km²).

London boundary: geoBoundaries · Office for National Statistics (Open Government Licence v3.0).

This compares size, not location: both shapes are at the same scale, north up, centred on each other.

What happened to each town

  1. Formosa do Rio Preto 25,899 inhabitants where it started
    7,455 ha reached on 11 Sept
    0.5 %
  2. Mateiros 2,748 inhabitants
    3,199 ha reached on 11 Sept
    0.3 %

Burnt area inside each municipality, from crossing the GWIS perimeter with administrative boundaries. The distance runs from the point marking the centre of each area to the nearest fire: staying a kilometre away does not mean it reached the houses.

People and buildings inside the perimeter

GHSL 2025
Built-up area< 0.1 ha
Residents< 20

Inside the perimeter there was no noticeable built-up land and almost nobody lived there (GHSL 2025, satellite-based estimate).

This is an estimate on 100 m cells, made from satellite imagery and census data: it does not mean that homes burned or that anyone was harmed. The perimeter also contains land that never burned. The GHSL 2025 epoch is a projection made from 2020 and earlier data.

Source: Global Human Settlement Layer (GHS-BUILT-S and GHS-POP R2023A), European Commission Joint Research Centre (JRC), © European Union, CC BY 4.0. Sum inside the perimeter computed by WorldFires. human-settlement.emergency.copernicus.eu

The weather day by day

ECMWF ERA5 reanalysis at the fire location, the standard reference for past weather, and the Canadian Fire Weather Index (the same system Copernicus uses), computed by WorldFires from that data. Days after the fire run until the first rain.

Open-Meteo.com (CC BY 4.0) · Copernicus Climate Change Service (ERA5)

Day High Min. humidity Peak gust Rain Danger (FWI)
11 Sept 34.7 °C 19 % 41 km/h 0.0 mm Extreme 52
12 Sept 35.9 °C 20 % 37 km/h 0.0 mm Very high 48
13 Sept 36.3 °C 19 % 43 km/h 0.0 mm Extreme 53
14 Sept 35.9 °C 21 % 48 km/h 0.0 mm Extreme 56
15 Sept 37.2 °C 19 % 43 km/h 0.0 mm Extreme 54
16 Sept 38.2 °C 15 % 27 km/h 0.0 mm Very high 48
17 Sept 37.1 °C 14 % 52 km/h 0.0 mm Extreme 64
18 Sept 35.3 °C 19 % 57 km/h 0.0 mm Extreme 69
19 Sept 34.7 °C 20 % 54 km/h 0.0 mm Extreme 68
20 Sept 34.8 °C 21 % 52 km/h 0.0 mm Extreme 65
21 Sept 36.1 °C 20 % 44 km/h 0.0 mm Extreme 59
22 Sept 37.0 °C 16 % 38 km/h 0.0 mm Extreme 52
23 Sept 37.0 °C 21 % 28 km/h 0.0 mm Very high 50
24 Sept after 36.8 °C 20 % 33 km/h 0.0 mm Very high 50
25 Sept after 31.6 °C 38 % 29 km/h 0.1 mm High 37
26 Sept after 32.5 °C 35 % 36 km/h 0.0 mm Very high 40
27 Sept after 35.7 °C 22 % 38 km/h 0.0 mm Very high 48
28 Sept after 35.8 °C 24 % 41 km/h 0.0 mm Very high 48
29 Sept after 35.7 °C 22 % 30 km/h 0.0 mm Very high 44
30 Sept after 37.3 °C 18 % 34 km/h 0.0 mm Extreme 50
1 Oct after 37.0 °C 18 % 34 km/h 0.0 mm Extreme 52
2 Oct after 31.6 °C 36 % 45 km/h 6.0 mm Moderate 14

Before and after, from space

Drag the line to compare the same ground before the fire and after it.

Before · 4 Sept 2026
After · 30 Sept 2026

If the day is cloudy, change the date: each satellite passes once a day. In false colour the burnt ground looks brown or red.

The smoke

CAMS · Copernicus

On 16 September 2026 the air beside the fire reached 95 µg/m³ of PM2.5. That day averaged 46: 3.0 times the WHO daily guideline (15).

PM2.5 peak95 µg/m³
Days over the guideline8 days
PM1096 µg/m³
Optical depth1.40
910111213141516171819202122232425
Good Fair Moderate Poor Very poor Extremely poor

Particles from the Copernicus CAMS model at the centre of the perimeter; these are not measurements in each town. The pale bar is the worst hour, the solid one the daily average.

Open-Meteo.com (CC BY 4.0) · Copernicus Atmosphere Monitoring Service (CAMS)

Detections table · 181Every satellite heat detection, one by one, with time, satellite, power and coordinates.
⬇ Download CSV Times in UTC. Each detection is a 375 m pixel: a large fire yields hundreds per pass.
Date and timeSatelliteFRP (MW)LatLon

Other fires nearby

All fires in Brazil ›

Frequently asked questions

How long did the Formosa do Rio Preto fire last?
According to the heat detections seen by satellite inside the perimeter, it burned from 11 September 2026 to 23 September 2026 (13 days). The perimeter dates it from 12 September 2026 to 21 September 2026.
How much area did it burn?
The perimeter GWIS (Copernicus) rebuilt from heat detections is 10,589 hectares (105.9 km²). It is an estimate: official national figures may differ.
Which municipalities burned?
The fire entered 2 municipalities: Formosa do Rio Preto (7,455 ha, 0.5 %); Mateiros (3,199 ha, 0.3 %).
What was the weather like?
During the fire the temperature reached 38.2 °C, humidity dropped to 14 % and gusts hit 57 km/h. The fire danger index (FWI) reached 69, class Extreme.
Where does this data come from?
From the GWIS (Copernicus) burnt perimeter, NASA FIRMS VIIRS hotspots and the administrative boundaries of Brazil (geoBoundaries). It is not an official report.

Where to verify it

A satellite detection is not an official report. Final figures and the fire’s status are published by each country’s emergency service.

Emergency number: 193 · Emergency number and official warnings ›

Satellite cross-check

History of this page · 1 Changes in area, dates, name, official record or merged pages, compared every night since 24 October 2026.
  1. Name: Mateiros → Formosa do Rio Preto.

RSS Changes to this page

Does something look wrong on this page?

This page is built from satellite data and official records, and it sometimes gets things wrong: the wrong dates, the wrong town, two fires merged into one, or something that was not a wildfire at all. If you know this fire first-hand (you live nearby, saw it, fought it or reported on it), tell us what really happened and we will check it.

Report an error
What do you think is wrong?

We will only use your email to reply about this report. Privacy. This is not an emergency service: if there is a fire now, call 193.

How we know this
  • Perimeter: GWIS (Copernicus), rebuilt from heat detections rather than mapped on imagery.
  • Dates adjusted with the VIIRS detections inside the perimeter, which said 12 September 2026 to 21 September 2026. 181 Suomi-NPP VIIRS detections on those dates.
  • We have not matched this page with any official record.
  • Weather: Copernicus ERA5 reanalysis at the fire location, in cells of about 25 km.
  • Built-up area and population come from the JRC Global Human Settlement Layer (epoch 2025, 100 m cells), summed inside the perimeter: an estimate of what was there, not a damage count.

How we build fire pages: methodology ›

Where this data comes from

The perimeter comes from the Copernicus Global Wildfire Information System (GWIS), which rebuilds it from MODIS and VIIRS heat detections and publishes it under CC BY 4.0. It is not measured on imagery as in Europe, so it is an estimate. Heat detections come from the VIIRS sensors aboard Suomi-NPP and NOAA-20, distributed by NASA FIRMS at 375 m resolution. Municipal boundaries come from geoBoundaries ADM2 (Creative Commons Attribution 3.0 Intergovernmental Organisations (CC BY 3.0 IGO)). The area per municipality is computed by WorldFires by crossing the perimeter with those boundaries, so it may differ from each country’s official figure.