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Ribeira do Piauí fire, August 2021 Ribeira do Piauí, Socorro do Piauí

Out · last detection 17 Sept 2021, 16:38 UTC

The fire started on 21 August 2021 in Ribeira do Piauí, Brazil, and satellites saw it burning for 29 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 6,324 hectares from heat detections, spread across 2 municipalities.

It is the 232th largest in Piaui since 2016 (of 805 with a page). Number 286 in Brazil in 2021, of 814.

Compare with…

Suggestions: Ribeira do Piauí · 2020São José do Peixe · 2022São José do Peixe · 2025Pedro Laurentino · 2024

Burnt area
6,324ha
GWIS perimeter (Copernicus)
Duration
29days
21 Aug 2021 – 18 Sept 2021
Municipalities hit
2
municipalities
Started on
21 Aug
2021
Heat detections
298
in a single hotspot: 87 MW
Danger at start
51
Extreme · FWI index
Average daily power
108MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 21 Aug18 Sept
17 Sept 2021

How it evolved, day by day

21 Aug 2021 · 14 MW · 2 22 Aug 2021 · 14 MW · 5 23 Aug 2021 · 29 MW · 3 24 Aug 2021 · 10 MW · 1 25 Aug 2021 · 50 MW · 8 26 Aug 2021 · 114 MW · 10 27 Aug 2021 · 47 MW · 11 28 Aug 2021 · 36 MW · 10 29 Aug 2021 · 22 MW · 6 30 Aug 2021 · 117 MW · 12 31 Aug 2021 · 2 MW · 2 3 Sept 2021 · 97 MW · 6 5 Sept 2021 · 6 MW · 4 6 Sept 2021 · 28 MW · 10 7 Sept 2021 · 90 MW · 5 8 Sept 2021 · 192 MW · 16 9 Sept 2021 · 71 MW · 7 10 Sept 2021 · 573 MW · 30 11 Sept 2021 · 524 MW · 76 12 Sept 2021 · 372 MW · 36 13 Sept 2021 · 109 MW · 14 14 Sept 2021 · 17 MW · 2 15 Sept 2021 · 21 MW · 5 16 Sept 2021 · 49 MW · 6 17 Sept 2021 · 87 MW · 11
21 Aug 25 Aug 29 Aug 5 Sept 9 Sept 10 Sept 13 Sept 17 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

39°high
48km/h · peak gust
15%lowest humidity

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

This area had burned before

15% of the perimeter overlaps earlier fires recorded since 2016: 928 ha in 2018.

How big is it?

10 km
It burned the equivalent of 4% of the area of London (63 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. Ribeira do Piauí 4,055 inhabitants where it started
    4,483 ha reached on 21 Aug
    4.4 %
  2. Socorro do Piauí 4,141 inhabitants
    1,882 ha reached on 10 Sept
    2.5 %

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 2020
Built-up area0.48 ha
Residents≈ 30

Inside the perimeter there were about 0.48 hectares of built-up land and about 30 residents (GHSL 2020, 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.

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)
21 Aug 35.4 °C 20 % 45 km/h 0.0 mm Extreme 51
22 Aug 36.0 °C 21 % 47 km/h 0.0 mm Extreme 53
23 Aug 36.3 °C 25 % 42 km/h 0.0 mm Extreme 51
24 Aug 36.5 °C 24 % 40 km/h 0.0 mm Extreme 52
25 Aug 36.5 °C 24 % 41 km/h 0.0 mm Very high 50
26 Aug 37.2 °C 22 % 43 km/h 0.0 mm Extreme 51
27 Aug 37.4 °C 22 % 43 km/h 0.0 mm Extreme 51
28 Aug 36.4 °C 26 % 48 km/h 0.0 mm Extreme 54
29 Aug 36.7 °C 21 % 45 km/h 0.0 mm Extreme 52
30 Aug 36.9 °C 23 % 42 km/h 0.0 mm Extreme 52
31 Aug 35.8 °C 25 % 42 km/h 0.0 mm Extreme 50
1 Sept 36.4 °C 25 % 39 km/h 0.0 mm Extreme 54
2 Sept 34.5 °C 26 % 41 km/h 0.0 mm Extreme 50
3 Sept 37.3 °C 20 % 40 km/h 0.0 mm Extreme 50
4 Sept 37.7 °C 27 % 47 km/h 0.0 mm Extreme 51
5 Sept 38.0 °C 23 % 39 km/h 0.0 mm Very high 47
6 Sept 38.7 °C 23 % 38 km/h 0.0 mm Very high 48
7 Sept 39.4 °C 15 % 41 km/h 0.0 mm Extreme 55
8 Sept 37.4 °C 21 % 42 km/h 0.0 mm Extreme 58
9 Sept 38.2 °C 20 % 37 km/h 0.0 mm Extreme 56
10 Sept 39.3 °C 18 % 38 km/h 0.0 mm Extreme 53
11 Sept 38.8 °C 16 % 38 km/h 0.0 mm Extreme 54
12 Sept 37.9 °C 15 % 42 km/h 0.0 mm Extreme 56
13 Sept 37.5 °C 21 % 42 km/h 0.0 mm Extreme 56
14 Sept 37.4 °C 22 % 40 km/h 0.0 mm Extreme 57
15 Sept 38.5 °C 21 % 37 km/h 0.0 mm Extreme 55
16 Sept 37.9 °C 16 % 41 km/h 0.0 mm Extreme 57
17 Sept 37.3 °C 18 % 45 km/h 0.0 mm Extreme 59
18 Sept 37.0 °C 17 % 43 km/h 0.0 mm Extreme 59
19 Sept after 38.5 °C 18 % 37 km/h 0.0 mm Extreme 53
20 Sept after 38.5 °C 18 % 36 km/h 0.0 mm Extreme 52
21 Sept after 38.4 °C 16 % 41 km/h 0.0 mm Extreme 56
22 Sept after 40.3 °C 17 % 37 km/h 0.0 mm Extreme 52
23 Sept after 37.0 °C 28 % 42 km/h 0.0 mm Very high 50
24 Sept after 36.3 °C 29 % 48 km/h 0.0 mm Extreme 54
25 Sept after 36.3 °C 29 % 48 km/h 0.0 mm Extreme 53
26 Sept after 37.8 °C 25 % 43 km/h 0.0 mm Very high 50
27 Sept after 37.9 °C 21 % 44 km/h 0.0 mm Extreme 50
28 Sept after 38.1 °C 18 % 45 km/h 0.0 mm Extreme 56

Before and after, from space

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

Before · 14 Aug 2021
After · 25 Sept 2021

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

Detections table · 298Every 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 Ribeira do Piauí fire last?
GWIS (Copernicus) dates it between 21 August 2021 and 18 September 2021: 29 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 6,324 hectares (63.2 km²). It is an estimate: official national figures may differ.
Which municipalities burned?
The fire entered 2 municipalities: Ribeira do Piauí (4,483 ha, 4.4 %); Socorro do Piauí (1,882 ha, 2.5 %).
What was the weather like?
During the fire the temperature reached 39.4 °C, humidity dropped to 15 % and gusts hit 48 km/h. The fire danger index (FWI) reached 59, 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. 298 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 2020, 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.