Skip to content
worldfires
BR · Brazil · –

Arraias fire, 25 September 2025 Arraias, Paranã

Out · last detection 3 Oct 2025, 04:12 UTC

The fire started on 25 September 2025 in Arraias, Brazil, and satellites saw it burning for 9 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 6,881 hectares from heat detections, spread across 2 municipalities.

It is the 310th largest in Tocantins since 2016 (of 1036 with a page). Number 181 in Brazil in 2025, of 526.

Burnt area
6,881ha
GWIS perimeter (Copernicus)
Duration
9days
25 Sept 2025 – 3 Oct 2025
Municipalities hit
2
municipalities
Started on
25 Sept
2025
Heat detections
174
in a single hotspot: 79 MW
Danger at start
43
Very high · FWI index
Average daily power
200MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 25 Sept3 Oct
3 Oct 2025

How it evolved, day by day

25 Sept 2025 · 8 MW · 1 26 Sept 2025 · 405 MW · 12 27 Sept 2025 · 120 MW · 23 28 Sept 2025 · 312 MW · 25 29 Sept 2025 · 186 MW · 20 30 Sept 2025 · 566 MW · 50 1 Oct 2025 · 130 MW · 34 2 Oct 2025 · 69 MW · 7 3 Oct 2025 · 5 MW · 2
25 Sept 27 Sept 30 Sept 3 Oct

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
53km/h · peak gust
8%lowest humidity

It had gone one day without rain (1 mm or more) when it started. Rain came after the fire: 2.4 mm on 13 Oct.

This area had burned before

49% of the perimeter overlaps earlier fires recorded since 2016: 2,016 ha in 2017, 812 ha in 2018, 1,395 ha in 2019. Part of it burned more than once, so the yearly figures add up to more than the 3,345 ha that had burned before.

How big is it?

10 km
It burned the equivalent of 4.3% of the area of London (69 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. Arraias 10,287 inhabitants where it started
    6,917 ha reached on 25 Sept
    1.2 %
  2. Paranã 10,542 inhabitants
    15 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 area0.10 ha
Residents< 20

Inside the perimeter there were about 0.10 hectares of 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)
25 Sept 34.7 °C 28 % 48 km/h 0.0 mm Very high 43
26 Sept 34.8 °C 29 % 53 km/h 0.0 mm Very high 48
27 Sept 34.3 °C 27 % 50 km/h 0.0 mm Very high 48
28 Sept 36.4 °C 10 % 43 km/h 0.0 mm Extreme 55
29 Sept 37.5 °C 12 % 36 km/h 0.0 mm Extreme 52
30 Sept 37.8 °C 8 % 45 km/h 0.0 mm Extreme 63
1 Oct 37.5 °C 14 % 38 km/h 0.0 mm Extreme 60
2 Oct 37.1 °C 11 % 40 km/h 0.0 mm Extreme 63
3 Oct 36.3 °C 18 % 49 km/h 0.0 mm Extreme 66
4 Oct after 35.8 °C 17 % 48 km/h 0.0 mm Extreme 64
5 Oct after 35.4 °C 23 % 44 km/h 0.0 mm Extreme 57
6 Oct after 36.6 °C 24 % 38 km/h 0.0 mm Very high 50
7 Oct after 38.7 °C 21 % 28 km/h 0.0 mm Very high 48
8 Oct after 37.4 °C 23 % 37 km/h 0.0 mm Extreme 52
9 Oct after 35.5 °C 29 % 41 km/h 0.0 mm Extreme 53
10 Oct after 35.5 °C 26 % 39 km/h 0.0 mm Very high 49
11 Oct after 36.4 °C 24 % 34 km/h 0.0 mm Extreme 50
12 Oct after 33.3 °C 35 % 36 km/h 0.4 mm High 37
13 Oct after 35.7 °C 29 % 26 km/h 2.4 mm Very high 38

Its twins: fires that started in the same weather

It started with an FWI of 42.7, a minimum humidity of 28% and 1 day without rain. Fires in the area that started in weather like this since 2016: 27.

FWI at the start 42.7
Minimum humidity 28 %
Days without rain 1
this fire chosen twins rest of the area
Almost identicalSimilar

Outlines of the closest twins

Cavalcante fire, October 2017
11,313 ha 13 days FWI 41.2 Min. humidity 28 % 25 km away, in 2017

First rain (1 mm or more) after it ended: 2.4 mm on 28 Oct.

What happened to them

10 days
median duration
5,505 ha
median area
26 %
went past 10,000 ha
2.4 mm
rain at the end (median; 21 of 27 had it)

It burned an area similar to its twins (6,881 ha against a median of 5,505 ha) and lasted 9 days, against 10 days.

In 6 of 27, 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 2.4 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

2.4 mmfirst rain
13 Oct10 days after it ended
53km/h · max. gust

It was considered over on 3 Oct, and on 13 Oct 2.4 mm fell. We do not know whether the rain or the firefighters put it out. Twins with rain when they ended: 21 of 27, with a median of 2.4 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 · 18 Sept 2025
After · 10 Oct 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 6 October 2025 the air beside the fire reached 38 µg/m³ of PM2.5. That day averaged 23: 1.5 times the WHO daily guideline (15).

PM2.5 peak38 µg/m³
Days over the guideline4 days
PM1039 µg/m³
Optical depth0.62
23 Sept26 Sept29 Sept2 Oct5 Oct
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 · 174Every 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 Arraias fire last?
GWIS (Copernicus) dates it between 25 September 2025 and 3 October 2025: 9 days between the first and last heat detection of the perimeter.
How much area did it burn?
The perimeter GWIS (Copernicus) rebuilt from heat detections is 6,881 hectares (68.8 km²). It is an estimate: official national figures may differ.
Which municipalities burned?
The fire entered 2 municipalities: Arraias (6,917 ha, 1.2 %); Paranã (15 ha, 0.0 %).
What was the weather like?
During the fire the temperature reached 37.8 °C, humidity dropped to 8 % and gusts hit 53 km/h. The fire danger index (FWI) reached 66, 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: 27. Their median duration was 10 days and their median area 5,505 ha; 26 % went past 10,000 ha. In 6 of 27, 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 2.4 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 Changes in area, dates, name, official record or merged pages, compared every night since 24 October 2026.

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 from the perimeter: the VIIRS detections inside it did not change them. 174 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.