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Grajaú fire, 23 September 2017 Grajaú

Out · last detection 7 Oct 2017, 16:57 UTC

The fire started on 23 September 2017 in Grajaú, Brazil, and satellites saw it burning for 15 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 4,273 hectares from heat detections, spread across a single municipality.

It is the 312th largest in Maranhão since 2016 (of 607 with a page). Number 587 in Brazil in 2017, of 994.

Compare with…

Suggestions: Grajaú · 2022Barra do Corda · 2017Grajaú · 2019Grajaú · 2016

Burnt area
4,273ha
GWIS perimeter (Copernicus)
Duration
15days
23 Sept 2017 – 7 Oct 2017
Municipalities hit
1
municipalities
Started on
23 Sept
2017
Heat detections
188
in a single hotspot: 91 MW
Danger at start
41
Very high · FWI index
Average daily power
172MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 23 Sept7 Oct
7 Oct 2017

How it evolved, day by day

23 Sept 2017 · 136 MW · 4 24 Sept 2017 · 384 MW · 16 25 Sept 2017 · 16 MW · 3 26 Sept 2017 · 138 MW · 13 27 Sept 2017 · 469 MW · 39 28 Sept 2017 · 541 MW · 64 29 Sept 2017 · 12 MW · 7 1 Oct 2017 · 36 MW · 10 2 Oct 2017 · 252 MW · 17 3 Oct 2017 · 44 MW · 7 6 Oct 2017 · 12 MW · 2 7 Oct 2017 · 24 MW · 6
23 Sept 25 Sept 27 Sept 28 Sept 29 Sept 2 Oct 6 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

38°high
45km/h · peak gust
29%lowest humidity

It had gone more than two months without rain (1 mm or more) when it started. Rain came after the fire: 1.3 mm on 16 Oct.

This area had burned before

No earlier perimeters overlap this fire since 2016, when the satellite record begins.

How big is it?

10 km
It burned the equivalent of 2.7% of the area of London (43 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. Grajaú 73,872 inhabitants where it started
    4,304 ha reached on 23 Sept
    0.5 %

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 2015
Built-up area< 0.1 ha
Residents< 20

Inside the perimeter there was no noticeable built-up land and almost nobody lived there (GHSL 2015, 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)
23 Sept 36.0 °C 31 % 39 km/h 0.0 mm Very high 41
24 Sept 35.9 °C 31 % 37 km/h 0.0 mm Very high 40
25 Sept 34.6 °C 36 % 32 km/h 0.0 mm High 36
26 Sept 37.3 °C 30 % 38 km/h 0.0 mm Very high 39
27 Sept 36.6 °C 32 % 44 km/h 0.0 mm Very high 41
28 Sept 37.0 °C 31 % 45 km/h 0.0 mm Very high 41
29 Sept 37.5 °C 31 % 43 km/h 0.0 mm Very high 41
30 Sept 35.7 °C 34 % 37 km/h 0.1 mm High 36
1 Oct 36.0 °C 33 % 37 km/h 0.0 mm Very high 39
2 Oct 36.6 °C 37 % 38 km/h 0.0 mm Very high 40
3 Oct 37.4 °C 36 % 38 km/h 0.0 mm High 36
4 Oct 37.1 °C 29 % 40 km/h 0.0 mm High 36
5 Oct 36.8 °C 31 % 41 km/h 0.0 mm Very high 42
6 Oct 37.2 °C 30 % 44 km/h 0.0 mm Very high 43
7 Oct 35.9 °C 33 % 39 km/h 0.0 mm Very high 41
8 Oct after 36.1 °C 33 % 36 km/h 0.0 mm High 38
9 Oct after 34.7 °C 41 % 31 km/h 0.1 mm High 32
10 Oct after 34.0 °C 41 % 35 km/h 0.0 mm High 30
11 Oct after 35.8 °C 36 % 45 km/h 0.2 mm High 33
12 Oct after 35.8 °C 43 % 44 km/h 0.0 mm High 35
13 Oct after 36.1 °C 39 % 40 km/h 0.0 mm High 32
14 Oct after 36.1 °C 40 % 38 km/h 0.1 mm High 32
15 Oct after 34.4 °C 47 % 36 km/h 0.0 mm High 31
16 Oct after 33.6 °C 52 % 32 km/h 1.3 mm Moderate 18

Before and after, from space

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

Before · 16 Sept 2017
After · 14 Oct 2017

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 · 188Every 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 Grajaú fire last?
According to the heat detections seen by satellite inside the perimeter, it burned from 23 September 2017 to 7 October 2017 (15 days). The perimeter dates it from 23 September 2017 to 3 October 2017.
How much area did it burn?
The perimeter GWIS (Copernicus) rebuilt from heat detections is 4,273 hectares (42.7 km²). It is an estimate: official national figures may differ.
Which municipalities burned?
The fire only entered Grajaú (4,304 ha, 0.5 %).
What was the weather like?
During the fire the temperature reached 37.5 °C, humidity dropped to 29 % and gusts hit 45 km/h. The fire danger index (FWI) reached 43, class Very high.
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. Last day with fire: 3 October 2017 → 7 October 2017.

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 23 September 2017 to 3 October 2017. 188 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 2015, 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.