How long did the Valença do Piauí fire last?

GWIS (Copernicus) dates it between 21 September 2018 and 26 September 2018: 6 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 3,272 hectares (32.7 km²). It is an estimate: official national figures may differ.

Which municipalities burned?

The fire only entered Valença do Piauí (3,293 ha, 2.4 %).

What was the weather like?

During the fire the temperature reached 38.3 °C, humidity dropped to 21 % and gusts hit 41 km/h. The fire danger index (FWI) reached 52, 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.

BR · Brazil · 2018-09-21 → 2018-09-26

Valença do Piauí fire, September 2018 Valença do Piauí

Out · last detection 27 Sept 2018, 16:00 UTC

The fire started on 21 September 2018 in Valença do Piauí, Brazil, and satellites saw it burning for 6 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 3,272 hectares from heat detections, spread across a single municipality.

It is the 702th largest in Piaui since 2016 (of 804 with a page). Number 250 in Brazil in 2018, of 291.

Compare with…

Suggestions: Valença do Piauí · 2016 Aroazes · 2026 Lagoa do Sítio · 2021 Valença do Piauí · 2023

Burnt area: 3,272ha; GWIS perimeter (Copernicus)
Duration: 6days; 21 Sept 2018 – 26 Sept 2018
Municipalities hit: 1; municipalities
Started on: 21 Sept; 2018
Heat detections: 103; in a single hotspot: 54 MW
Danger at start: 52; Extreme · FWI index
Average daily power: 144MW; detected power per day, on average

HOTSPOTS BY DAY 21 Sept26 Sept

Play back 27 Sept 2018

How it evolved, day by day

21 Sept 22 Sept 23 Sept 24 Sept 25 Sept 26 Sept 27 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

41km/h · peak gust

21%lowest humidity

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

This area had burned before

73% of the perimeter overlaps earlier fires recorded since 2016: 2,393 ha in 2016.

2,393 ha Valença do Piauí fire, August 2016 4,003 ha in total; the hectares shown are those it shares with this fire

How big is it?

It burned the equivalent of 2.1% of the area of London (33 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

Valença do Piauí 22,279 inhabitants where it started

3,293 ha reached on 21 Sept

2.4 %

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.

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 Sept	37.9 °C	22 %	41 km/h	0.0 mm	Extreme 52
22 Sept	37.6 °C	24 %	37 km/h	0.0 mm	Very high 49
23 Sept	38.1 °C	25 %	35 km/h	0.0 mm	Very high 48
24 Sept	37.3 °C	28 %	33 km/h	0.0 mm	Very high 44
25 Sept	36.7 °C	28 %	36 km/h	0.0 mm	Very high 46
26 Sept	37.0 °C	30 %	38 km/h	0.0 mm	Very high 44
27 Sept after	38.3 °C	21 %	39 km/h	0.0 mm	Very high 46
28 Sept after	38.6 °C	23 %	40 km/h	0.0 mm	Very high 48
29 Sept after	38.8 °C	20 %	35 km/h	0.0 mm	Very high 45
30 Sept after	37.6 °C	28 %	39 km/h	0.0 mm	Very high 49
1 Oct after	36.6 °C	31 %	37 km/h	0.0 mm	Very high 44
2 Oct after	37.4 °C	28 %	33 km/h	0.0 mm	Very high 42
3 Oct after	38.3 °C	25 %	32 km/h	0.0 mm	Very high 43
4 Oct after	38.6 °C	27 %	37 km/h	0.0 mm	Very high 45
5 Oct after	37.7 °C	29 %	27 km/h	0.0 mm	Very high 41
6 Oct after	35.3 °C	43 %	28 km/h	0.7 mm	High 26
7 Oct after	36.6 °C	33 %	35 km/h	0.0 mm	High 33

Before and after, from space

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

↔

Before · 14 Sept 2018

After · 3 Oct 2018

Before After

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 · 103Every 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 time	Satellite	FRP (MW)	Lat	Lon

Other fires nearby

All fires in Brazil ›

Frequently asked questions

How long did the Valença do Piauí fire last?: GWIS (Copernicus) dates it between 21 September 2018 and 26 September 2018: 6 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 3,272 hectares (32.7 km²). It is an estimate: official national figures may differ.
Which municipalities burned?: The fire only entered Valença do Piauí (3,293 ha, 2.4 %).
What was the weather like?: During the fire the temperature reached 38.3 °C, humidity dropped to 21 % and gusts hit 41 km/h. The fire danger index (FWI) reached 52, 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 ›

INPE · Programa Queimadas ↗
IBAMA · Prevfogo ↗

Satellite cross-check

NASA FIRMS ↗
GWIS · Copernicus ↗

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.

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What really happened?

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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. 103 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.

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.

Where it burned