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Oeiras fire, September 2023 Oeiras, Colônia do Piauí

Out · last detection 13 Oct 2023, 15:23 UTC

The fire started on 29 September 2023 in Oeiras, Brazil, and satellites saw it burning for 14 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 13,580 hectares from heat detections, spread across 2 municipalities.

It is the 65th largest in Piaui since 2016 (of 805 with a page). Number 32 in Brazil in 2023, of 431.

Compare with…

Suggestions: Colônia do Piauí · 2018Oeiras · 2021Oeiras · 2016Oeiras · 2016

Burnt area
13,580ha
GWIS perimeter (Copernicus)
Duration
14days
29 Sept 2023 – 12 Oct 2023
Municipalities hit
2
municipalities
Started on
29 Sept
2023
Heat detections
492
in a single hotspot: 467 MW
Danger at start
42
Very high · FWI index
Average daily power
575MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 29 Sept12 Oct
13 Oct 2023

How it evolved, day by day

29 Sept 2023 · 852 MW · 36 30 Sept 2023 · 224 MW · 23 1 Oct 2023 · 273 MW · 26 2 Oct 2023 · 470 MW · 63 3 Oct 2023 · 3,483 MW · 71 4 Oct 2023 · 2,058 MW · 156 5 Oct 2023 · 112 MW · 25 6 Oct 2023 · 697 MW · 44 7 Oct 2023 · 116 MW · 13 8 Oct 2023 · 5 MW · 3 9 Oct 2023 · 38 MW · 6 10 Oct 2023 · 278 MW · 22 11 Oct 2023 · 7 MW · 1 12 Oct 2023 · 12 MW · 2 13 Oct 2023 · 5 MW · 1
29 Sept 2 Oct 3 Oct 5 Oct 8 Oct 11 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

39°high
43km/h · peak gust
18%lowest humidity

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

This area had burned before

92% of the perimeter overlaps earlier fires recorded since 2016: 6,299 ha in 2016, 980 ha in 2017, 4,476 ha in 2018, 1,387 ha in 2019, 5,449 ha in 2020, 7,076 ha in 2021, 692 ha in 2022. Part of it burned more than once, so the yearly figures add up to more than the 12,497 ha that had burned before.

How big is it?

10 km
It burned the equivalent of 8.6% of the area of London (136 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. Oeiras 38,161 inhabitants where it started
    10,301 ha reached on 29 Sept
    3.8 %
  2. Colônia do Piauí 6,994 inhabitants
    3,369 ha reached on 30 Sept
    3.5 %

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 area1.0 ha
Residents≈ 60

Inside the perimeter there were about 1.0 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)

Day High Min. humidity Peak gust Rain Danger (FWI)
29 Sept 39.0 °C 19 % 23 km/h 0.0 mm Very high 42
30 Sept 38.1 °C 21 % 41 km/h 0.0 mm Extreme 53
1 Oct 38.0 °C 19 % 43 km/h 0.0 mm Extreme 53
2 Oct 39.1 °C 18 % 34 km/h 0.0 mm Very high 49
3 Oct 39.2 °C 20 % 27 km/h 0.0 mm Very high 45
4 Oct 37.8 °C 26 % 28 km/h 0.0 mm Very high 44
5 Oct 38.0 °C 24 % 30 km/h 0.0 mm Very high 47
6 Oct 38.4 °C 21 % 28 km/h 0.0 mm Very high 44
7 Oct 37.1 °C 28 % 27 km/h 0.0 mm Very high 42
8 Oct 37.4 °C 26 % 31 km/h 0.0 mm Very high 44
9 Oct 38.0 °C 22 % 28 km/h 0.0 mm Very high 42
10 Oct 38.3 °C 25 % 27 km/h 0.0 mm Very high 43
11 Oct 36.6 °C 24 % 30 km/h 0.0 mm Very high 44
12 Oct 36.7 °C 26 % 37 km/h 0.0 mm Very high 49
13 Oct after 37.6 °C 26 % 24 km/h 0.0 mm Very high 41
14 Oct after 38.5 °C 24 % 30 km/h 0.0 mm Very high 45
15 Oct after 36.1 °C 29 % 33 km/h 0.0 mm Very high 45
16 Oct after 36.2 °C 24 % 44 km/h 0.0 mm Extreme 50
17 Oct after 37.2 °C 17 % 42 km/h 0.0 mm Extreme 52
18 Oct after 37.7 °C 17 % 41 km/h 0.0 mm Extreme 53
19 Oct after 37.6 °C 22 % 23 km/h 0.0 mm Very high 43
20 Oct after 38.6 °C 18 % 34 km/h 0.0 mm Very high 48
21 Oct after 38.5 °C 22 % 42 km/h 0.0 mm Extreme 55
22 Oct after 37.7 °C 25 % 38 km/h 0.0 mm Very high 50

Before and after, from space

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

Before · 22 Sept 2023
After · 19 Oct 2023

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 7 October 2023 the air beside the fire reached 26 µg/m³ of PM2.5, but no daily average passed the WHO guideline (15).

PM2.5 peak26 µg/m³
Days over the guideline0 days
PM1037 µg/m³
Optical depth0.42
27282930123456789101112131415
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 · 492Every 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 Oeiras fire last?
GWIS (Copernicus) dates it between 29 September 2023 and 12 October 2023: 14 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 13,580 hectares (135.8 km²). It is an estimate: official national figures may differ.
Which municipalities burned?
The fire entered 2 municipalities: Oeiras (10,301 ha, 3.8 %); Colônia do Piauí (3,369 ha, 3.5 %).
What was the weather like?
During the fire the temperature reached 39.2 °C, humidity dropped to 18 % and gusts hit 43 km/h. The fire danger index (FWI) reached 53, 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 Changes in area, dates, name, official record or merged pages, compared every night since 24 October 2026.

No changes since 24 October 2026.

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 from the perimeter: the VIIRS detections inside it did not change them. 492 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.