Skip to content
worldfires
en
BR · Brazil · →

Lagoa do Sítio fire, 18 August 2021 Valença do Piauí, Lagoa do Sítio, Pimenteiras

Out · last detection 12 Sept 2021, 16:32 UTC

The fire started on 18 August 2021 in Lagoa do Sítio, Brazil, and satellites saw it burning for 26 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 12,070 hectares from heat detections, spread across 3 municipalities.

It is the 86th largest in Piaui since 2016 (of 805 with a page). Number 125 in Brazil in 2021, of 814.

Compare with…

Suggestions: Valença do Piauí · 2019Lagoa do Sítio · 2019Aroazes · 2026Lagoa do Sítio · 2021

Burnt area
12,070ha
GWIS perimeter (Copernicus)
Duration
26days
18 Aug 2021 – 12 Sept 2021
Municipalities hit
3
municipalities
Started on
18 Aug
2021
Heat detections
423
in a single hotspot: 161 MW
Danger at start
48
Very high · FWI index
Average daily power
217MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 18 Aug12 Sept
12 Sept 2021

How it evolved, day by day

18 Aug 2021 · 29 MW · 2 19 Aug 2021 · 75 MW · 9 20 Aug 2021 · 4 MW · 2 21 Aug 2021 · 5 MW · 7 22 Aug 2021 · 1,007 MW · 46 23 Aug 2021 · 117 MW · 20 24 Aug 2021 · 413 MW · 41 25 Aug 2021 · 1,016 MW · 18 26 Aug 2021 · 533 MW · 42 27 Aug 2021 · 471 MW · 76 28 Aug 2021 · 236 MW · 22 29 Aug 2021 · 595 MW · 36 30 Aug 2021 · 37 MW · 5 31 Aug 2021 · 6 MW · 4 1 Sept 2021 · 9 MW · 1 2 Sept 2021 · 40 MW · 11 3 Sept 2021 · 53 MW · 11 4 Sept 2021 · 19 MW · 4 5 Sept 2021 · 57 MW · 11 6 Sept 2021 · 63 MW · 6 7 Sept 2021 · 560 MW · 31 8 Sept 2021 · 26 MW · 7 10 Sept 2021 · 31 MW · 6 11 Sept 2021 · 9 MW · 3 12 Sept 2021 · 9 MW · 2
18 Aug 22 Aug 25 Aug 26 Aug 30 Aug 3 Sept 7 Sept 12 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

37°high
49km/h · peak gust
15%lowest humidity

It had gone 46 days without rain (1 mm or more) when it started.

This area had burned before

23% of the perimeter overlaps earlier fires recorded since 2016: 2,740 ha in 2019.

How big is it?

10 km
It burned the equivalent of 7.6% of the area of London (121 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. Valença do Piauí 22,279 inhabitants
    9,615 ha reached on 23 Aug
    7.2 %
  2. Lagoa do Sítio 4,520 inhabitants where it started
    2,050 ha reached on 18 Aug
    2.5 %
  3. Pimenteiras 11,341 inhabitants
    483 ha reached on 21 Aug
    0.1 %

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 area2.3 ha
Residents≈ 200

Inside the perimeter there were about 2.3 hectares of built-up land and about 200 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)
18 Aug 34.3 °C 20 % 41 km/h 0.0 mm Very high 48
19 Aug 33.9 °C 24 % 44 km/h 0.0 mm Very high 49
20 Aug 34.0 °C 29 % 45 km/h 0.0 mm Very high 46
21 Aug 34.1 °C 23 % 42 km/h 0.0 mm Very high 46
22 Aug 34.9 °C 24 % 44 km/h 0.0 mm Very high 47
23 Aug 36.2 °C 22 % 43 km/h 0.0 mm Very high 47
24 Aug 34.2 °C 29 % 42 km/h 0.0 mm Very high 45
25 Aug 34.9 °C 24 % 39 km/h 0.0 mm Very high 44
26 Aug 36.0 °C 24 % 41 km/h 0.0 mm Very high 45
27 Aug 35.8 °C 26 % 41 km/h 0.0 mm Very high 46
28 Aug 35.2 °C 23 % 49 km/h 0.0 mm Extreme 51
29 Aug 35.9 °C 18 % 47 km/h 0.0 mm Extreme 53
30 Aug 35.5 °C 25 % 41 km/h 0.0 mm Very high 49
31 Aug 34.7 °C 26 % 38 km/h 0.0 mm Very high 45
1 Sept 34.2 °C 26 % 38 km/h 0.0 mm Very high 46
2 Sept 35.5 °C 23 % 35 km/h 0.0 mm Very high 46
3 Sept 35.7 °C 23 % 34 km/h 0.0 mm Very high 47
4 Sept 35.6 °C 23 % 45 km/h 0.0 mm Very high 48
5 Sept 37.1 °C 17 % 41 km/h 0.0 mm Extreme 51
6 Sept 36.2 °C 26 % 38 km/h 0.0 mm Very high 46
7 Sept 37.1 °C 19 % 34 km/h 0.0 mm Very high 44
8 Sept 35.6 °C 23 % 34 km/h 0.0 mm Very high 45
9 Sept 36.5 °C 23 % 30 km/h 0.0 mm Very high 43
10 Sept 36.9 °C 22 % 30 km/h 0.0 mm Very high 44
11 Sept 37.3 °C 21 % 32 km/h 0.0 mm Very high 46
12 Sept 36.5 °C 15 % 35 km/h 0.0 mm Very high 50
13 Sept after 35.8 °C 23 % 41 km/h 0.0 mm Extreme 51
14 Sept after 35.4 °C 25 % 36 km/h 0.0 mm Very high 47
15 Sept after 35.3 °C 30 % 37 km/h 0.0 mm Very high 44
16 Sept after 35.2 °C 26 % 34 km/h 0.0 mm Very high 41
17 Sept after 35.6 °C 21 % 40 km/h 0.0 mm Very high 46
18 Sept after 34.8 °C 26 % 38 km/h 0.0 mm Very high 47
19 Sept after 36.5 °C 24 % 34 km/h 0.0 mm Very high 44
20 Sept after 35.9 °C 25 % 32 km/h 0.0 mm Very high 44
21 Sept after 36.0 °C 27 % 33 km/h 0.0 mm Very high 42
22 Sept after 36.4 °C 26 % 33 km/h 0.0 mm Very high 43

Before and after, from space

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

Before · 11 Aug 2021
After · 19 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 · 423Every 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 Lagoa do Sítio fire last?
According to the heat detections seen by satellite inside the perimeter, it burned from 18 August 2021 to 12 September 2021 (26 days). The perimeter dates it from 19 August 2021 to 12 September 2021.
How much area did it burn?
The perimeter GWIS (Copernicus) rebuilt from heat detections is 12,070 hectares (120.7 km²). It is an estimate: official national figures may differ.
Which municipalities burned?
The fire entered 3 municipalities: Valença do Piauí (9,615 ha, 7.2 %); Lagoa do Sítio (2,050 ha, 2.5 %); Pimenteiras (483 ha, 0.1 %).
What was the weather like?
During the fire the temperature reached 37.3 °C, humidity dropped to 15 % and gusts hit 49 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 · 1 Changes in area, dates, name, official record or merged pages, compared every night since 24 October 2026.
  1. Start date: 19 August 2021 → 18 August 2021.

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 adjusted with the VIIRS detections inside the perimeter, which said 19 August 2021 to 12 September 2021. 423 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.