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Formosa do Rio Preto fire, August 2025 Formosa do Rio Preto, Santa Rita de Cássia

Out · last detection 4 Sept 2025, 04:55 UTC

The fire started on 21 August 2025 in Formosa do Rio Preto, Brazil, and satellites saw it burning for 15 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 5,340 hectares from heat detections, spread across 2 municipalities.

It is the 186th largest in Bahia since 2016 (of 386 with a page). Number 256 in Brazil in 2025, of 526.

Burnt area
5,340ha
GWIS perimeter (Copernicus)
Duration
15days
21 Aug 2025 – 4 Sept 2025
Municipalities hit
2
municipalities
Started on
21 Aug
2025
Heat detections
227
in a single hotspot: 244 MW
Danger at start
50
Very high · FWI index
Average daily power
165MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 21 Aug4 Sept
4 Sept 2025

How it evolved, day by day

21 Aug 2025 · 505 MW · 3 22 Aug 2025 · 1 MW · 1 24 Aug 2025 · 79 MW · 10 25 Aug 2025 · 217 MW · 34 26 Aug 2025 · 84 MW · 15 27 Aug 2025 · 184 MW · 30 28 Aug 2025 · 69 MW · 18 29 Aug 2025 · 242 MW · 21 30 Aug 2025 · 703 MW · 52 31 Aug 2025 · 163 MW · 23 1 Sept 2025 · 45 MW · 11 2 Sept 2025 · 8 MW · 2 3 Sept 2025 · 7 MW · 1 4 Sept 2025 · 6 MW · 6
21 Aug 25 Aug 30 Aug 3 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

34°high
45km/h · peak gust
16%lowest humidity

It had gone more than two months without rain (1 mm or more) when it started.

This area had burned before

55% of the perimeter overlaps earlier fires recorded since 2016: 1,738 ha in 2019, 1,545 ha in 2021. Part of it burned more than once, so the yearly figures add up to more than the 2,958 ha that had burned before.

How big is it?

10 km
It burned the equivalent of 3.4% of the area of London (53 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
    5,346 ha reached on 21 Aug
    0.3 %
  2. Santa Rita de Cássia 27,390 inhabitants
    35 ha
    0.0 %

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 area0.42 ha
Residents≈ 60

Inside the perimeter there were about 0.42 hectares of built-up land and about 60 residents (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)

Started with 60 days without rain: 55 % of the area in Brazil

Day High Min. humidity Peak gust Rain Danger (FWI)
21 Aug 33.1 °C 16 % 35 km/h 0.0 mm Very high 50
22 Aug 33.6 °C 18 % 40 km/h 0.0 mm Extreme 54
23 Aug 32.7 °C 20 % 36 km/h 0.0 mm Extreme 52
24 Aug 33.0 °C 24 % 34 km/h 0.0 mm Very high 45
25 Aug 33.7 °C 23 % 38 km/h 0.0 mm Extreme 50
26 Aug 33.5 °C 27 % 37 km/h 0.0 mm Extreme 51
27 Aug 34.3 °C 23 % 37 km/h 0.0 mm Very high 48
28 Aug 34.0 °C 23 % 34 km/h 0.0 mm Very high 49
29 Aug 33.9 °C 21 % 34 km/h 0.0 mm Very high 48
30 Aug 33.9 °C 24 % 35 km/h 0.0 mm Very high 47
31 Aug 34.3 °C 22 % 37 km/h 0.0 mm Extreme 52
1 Sept 33.0 °C 26 % 40 km/h 0.0 mm Extreme 53
2 Sept 32.5 °C 26 % 41 km/h 0.0 mm Extreme 56
3 Sept 33.3 °C 24 % 45 km/h 0.0 mm Extreme 55
4 Sept 33.2 °C 26 % 43 km/h 0.0 mm Extreme 51
5 Sept after 33.2 °C 25 % 34 km/h 0.0 mm Very high 48
6 Sept after 34.9 °C 20 % 32 km/h 0.0 mm Extreme 50
7 Sept after 34.9 °C 23 % 34 km/h 0.0 mm Extreme 52
8 Sept after 34.4 °C 22 % 35 km/h 0.0 mm Very high 48
9 Sept after 34.8 °C 21 % 34 km/h 0.0 mm Very high 48
10 Sept after 38.4 °C 11 % 35 km/h 0.0 mm Extreme 58
11 Sept after 37.4 °C 18 % 35 km/h 0.0 mm Extreme 59
12 Sept after 36.6 °C 19 % 34 km/h 0.0 mm Extreme 59
13 Sept after 35.8 °C 20 % 36 km/h 0.0 mm Extreme 56
14 Sept after 36.0 °C 19 % 37 km/h 0.0 mm Extreme 57

Its twins: fires that started in the same weather

It started with an FWI of 49.5, a minimum humidity of 16% and more than two months without rain. Fires in the area that started in weather like this since 2016: 34.

FWI at the start 49.5
Minimum humidity 16 %
Days without rain 60+
this fire chosen twins rest of the area
Almost identicalSimilar

Outlines of the closest twins

Cotegipe fire, October 2024
4,155 ha 9 days FWI 51.0 Min. humidity 17 % 79 km away, in 2024

First rain (1 mm or more) after it ended: 1.3 mm on 16 Oct.

What happened to them

9 days
median duration
4,437 ha
median area
12 %
went past 10,000 ha
4.2 mm
rain at the end (median; 19 of 34 had it)

It burned an area similar to its twins (5,340 ha against a median of 4,437 ha) and lasted 15 days, against 9 days.

In 15 of 34, not even 1 mm fell in the ten days after the end: they went out without rain. In the rest, the first rainy day brought a median of 4.2 mm.

This is a bank of analogues: it shows what usually happens, not what will happen. With fewer than 15 twins we give no figures. How we calculate it

How it ended

—first rain
—no rain in ten days
45km/h · max. gust

It was considered over on 4 Sept, and not even 1 mm fell in the following ten days: it went out without rain. Twins with rain when they ended: 19 of 34, with a median of 4.2 mm.

Weather on this page: Open-Meteo.com (CC BY 4.0) · Copernicus Climate Change Service (ERA5)

How a twin is chosen

  • Same area: fires that have already ended, less than 250 km from this one, since 2016.
  • Same start: we compare the FWI on the first day, the minimum humidity that day and the run of days without rain before it. The slider sets how much they may differ.
  • Only pages with final weather data (ERA5 reanalysis) calculated in the same way as this fire’s; agricultural and grass burns and pages with data under review are left out.
  • Fires burning at the same time as this one (a week before or after) are left out: they share the same spell of weather and do not count as a precedent.
  • They are sorted by similarity, and the outlines of the first five are drawn.

How we calculate it

Before and after, from space

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

Before · 14 Aug 2025
After · 11 Sept 2025

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 1 September 2025 the air beside the fire reached 27 µg/m³ of PM2.5, but no daily average passed the WHO guideline (15).

PM2.5 peak27 µg/m³
Days over the guideline0 days
PM1028 µg/m³
Optical depth0.35
19 Aug23 Aug27 Aug31 Aug4 Sept
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 · 227Every 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 21 August 2025 to 4 September 2025 (15 days). The perimeter dates it from 23 August 2025 to 2 September 2025.
How much area did it burn?
The perimeter GWIS (Copernicus) rebuilt from heat detections is 5,340 hectares (53.4 km²). It is an estimate: official national figures may differ.
Which municipalities burned?
The fire entered 2 municipalities: Formosa do Rio Preto (5,346 ha, 0.3 %); Santa Rita de Cássia (35 ha, 0.0 %).
What was the weather like?
During the fire the temperature reached 34.3 °C, humidity dropped to 16 % and gusts hit 45 km/h. The fire danger index (FWI) reached 56, 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.
How did the fires that started in similar weather in this area end?
Fires less than 250 km away that started since 2016 with a similar FWI, humidity and dry spell: 34. Their median duration was 9 days and their median area 4,437 ha; 12 % went past 10,000 ha. In 15 of 34, not even 1 mm fell in the ten days after the end: they went out without rain. In the rest, the first rainy day brought a median of 4.2 mm.

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 · 2 Changes in area, dates, name, official record or merged pages, compared every night since 24 October 2026.
  1. Last day with fire: 2 September 2025 → 4 September 2025.
  2. Start date: 23 August 2025 → 21 August 2025.

RSS Changes to this page With cross-checks and a citable version

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 23 August 2025 to 2 September 2025. 227 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.