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Gilbués fire, September 2023 Gilbués, São Gonçalo do Gurguéia, Riacho Frio

Out · last detection 26 Sept 2023, 15:41 UTC

The fire started on 18 September 2023 in Gilbués, Brazil, and satellites saw it burning for 9 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 5,629 hectares from heat detections, spread across 3 municipalities.

It is the 282th largest in Piaui since 2016 (of 804 with a page). Number 141 in Brazil in 2023, of 431.

Compare with…

Suggestions: Riacho Frio · 2025Riacho Frio · 2021Riacho Frio · 2023Riacho Frio · 2026

Burnt area
5,629ha
GWIS perimeter (Copernicus)
Duration
9days
18 Sept 2023 – 26 Sept 2023
Municipalities hit
3
municipalities
Started on
18 Sept
2023
Heat detections
255
in a single hotspot: 66 MW
Danger at start
53
Extreme · FWI index
Average daily power
282MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 18 Sept26 Sept
26 Sept 2023

How it evolved, day by day

18 Sept 2023 · 275 MW · 25 19 Sept 2023 · 382 MW · 23 20 Sept 2023 · 451 MW · 34 21 Sept 2023 · 673 MW · 64 22 Sept 2023 · 357 MW · 56 23 Sept 2023 · 231 MW · 27 24 Sept 2023 · 90 MW · 15 25 Sept 2023 · 70 MW · 9 26 Sept 2023 · 12 MW · 2
18 Sept 20 Sept 21 Sept 22 Sept 24 Sept 26 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
40km/h · peak gust
15%lowest humidity

It had gone 19 days without rain (1 mm or more) when it started.

This area had burned before

37% of the perimeter overlaps earlier fires recorded since 2016: 40 ha in 2019, 1,977 ha in 2020, 105 ha in 2022.

How big is it?

10 km
It burned the equivalent of 3.6% of the area of London (56 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. Gilbués 10,892 inhabitants where it started
    3,462 ha reached on 18 Sept
    1.0 %
  2. São Gonçalo do Gurguéia 2,947 inhabitants
    1,632 ha reached on 21 Sept
    1.2 %
  3. Riacho Frio 4,165 inhabitants
    574 ha reached on 18 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 area3.9 ha
Residents≈ 350

Inside the perimeter there were about 3.9 hectares of built-up land and about 350 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)
18 Sept 36.3 °C 18 % 38 km/h 0.0 mm Extreme 53
19 Sept 35.5 °C 26 % 40 km/h 0.0 mm Very high 48
20 Sept 36.3 °C 25 % 37 km/h 0.0 mm Very high 47
21 Sept 36.3 °C 17 % 39 km/h 0.0 mm Very high 49
22 Sept 36.7 °C 21 % 39 km/h 0.0 mm Extreme 51
23 Sept 38.2 °C 15 % 32 km/h 0.0 mm Very high 48
24 Sept 38.3 °C 20 % 34 km/h 0.0 mm Extreme 50
25 Sept 38.1 °C 23 % 30 km/h 0.0 mm Very high 45
26 Sept 37.7 °C 26 % 23 km/h 0.0 mm Very high 43
27 Sept after 34.0 °C 42 % 26 km/h 0.0 mm High 33
28 Sept after 34.1 °C 43 % 36 km/h 0.8 mm High 26
29 Sept after 38.6 °C 19 % 31 km/h 0.0 mm Very high 44
30 Sept after 37.9 °C 14 % 34 km/h 0.0 mm Extreme 51
1 Oct after 38.2 °C 15 % 34 km/h 0.0 mm Extreme 51
2 Oct after 38.3 °C 17 % 27 km/h 0.0 mm Very high 48
3 Oct after 38.5 °C 21 % 40 km/h 0.0 mm Extreme 52
4 Oct after 37.3 °C 21 % 42 km/h 0.0 mm Extreme 58
5 Oct after 38.6 °C 23 % 37 km/h 0.0 mm Extreme 52
6 Oct after 37.3 °C 26 % 40 km/h 0.1 mm Extreme 51

Before and after, from space

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

Before · 11 Sept 2023
After · 3 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 23 September 2023 the air beside the fire reached 55 µg/m³ of PM2.5. That day averaged 28: 1.9 times the WHO daily guideline (15).

PM2.5 peak55 µg/m³
Days over the guideline6 days
PM1078 µg/m³
Optical depth0.71
1617181920212223242526272829
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 · 255Every 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 Gilbués fire last?
GWIS (Copernicus) dates it between 18 September 2023 and 26 September 2023: 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 5,629 hectares (56.3 km²). It is an estimate: official national figures may differ.
Which municipalities burned?
The fire entered 3 municipalities: Gilbués (3,462 ha, 1.0 %); São Gonçalo do Gurguéia (1,632 ha, 1.2 %); Riacho Frio (574 ha, 0.3 %).
What was the weather like?
During the fire the temperature reached 38.3 °C, humidity dropped to 15 % and gusts hit 40 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. 255 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.