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Altamira fire, 4 September 2023 Altamira

Out · last detection 22 Sept 2023, 16:58 UTC

The fire started on 4 September 2023 in Altamira, Brazil, and satellites saw it burning for 19 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 3,644 hectares from heat detections, spread across a single municipality.

It is the 696th largest in Pará since 2016 (of 957 with a page). Number 309 in Brazil in 2023, of 430.

Compare with…

Suggestions: São Félix do Xingu · 2022Altamira · 2022Altamira · 2020Altamira · 2026

Burnt area
3,644ha
GWIS perimeter (Copernicus)
Duration
19days
4 Sept 2023 – 22 Sept 2023
Municipalities hit
1
municipalities
Started on
4 Sept
2023
Heat detections
236
in a single hotspot: 44 MW
Danger at start
32
High · FWI index
Average daily power
82MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 4 Sept22 Sept
22 Sept 2023

How it evolved, day by day

4 Sept 2023 · 61 MW · 12 5 Sept 2023 · 179 MW · 23 6 Sept 2023 · 214 MW · 33 7 Sept 2023 · 23 MW · 6 9 Sept 2023 · 26 MW · 11 10 Sept 2023 · 55 MW · 14 11 Sept 2023 · 255 MW · 30 12 Sept 2023 · 136 MW · 18 13 Sept 2023 · 31 MW · 11 14 Sept 2023 · 167 MW · 27 15 Sept 2023 · 115 MW · 36 16 Sept 2023 · 31 MW · 11 18 Sept 2023 · 6 MW · 1 19 Sept 2023 · 1 MW · 1 21 Sept 2023 · 17 MW · 1 22 Sept 2023 · 3 MW · 1
4 Sept 11 Sept 18 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

36°high
48km/h · peak gust
30%lowest humidity

It had gone 51 days without rain (1 mm or more) when it started. Rain came after the fire: 4.6 mm on 28 Sept.

This area had burned before

48% of the perimeter overlaps earlier fires recorded since 2016: 96 ha in 2017, 2,217 ha in 2020. Part of it burned more than once, so the yearly figures add up to more than the 1,753 ha that had burned before.

How big is it?

10 km
It burned the equivalent of 2.3% of the area of London (36 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. Altamira 126,279 inhabitants where it started
    3,665 ha reached on 4 Sept
    0.0 %

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 area< 0.1 ha
Residents< 20

Inside the perimeter there was no noticeable built-up land and almost nobody lived there (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)
4 Sept 34.2 °C 36 % 30 km/h 0.0 mm High 32
5 Sept 35.6 °C 30 % 32 km/h 0.0 mm High 35
6 Sept 33.9 °C 34 % 27 km/h 0.0 mm High 31
7 Sept 32.4 °C 45 % 35 km/h 0.2 mm High 33
8 Sept 34.2 °C 38 % 48 km/h 0.0 mm High 36
9 Sept 34.2 °C 39 % 36 km/h 0.0 mm High 34
10 Sept 35.0 °C 36 % 41 km/h 0.1 mm High 36
11 Sept 33.6 °C 39 % 36 km/h 0.1 mm High 36
12 Sept 33.9 °C 37 % 42 km/h 0.0 mm High 36
13 Sept 34.8 °C 35 % 37 km/h 0.0 mm High 38
14 Sept 34.8 °C 34 % 30 km/h 0.0 mm High 29
15 Sept 35.4 °C 36 % 35 km/h 0.0 mm High 34
16 Sept 34.3 °C 44 % 30 km/h 0.1 mm High 33
17 Sept 33.5 °C 45 % 37 km/h 0.2 mm High 32
18 Sept 34.0 °C 40 % 32 km/h 0.1 mm High 34
19 Sept 34.0 °C 41 % 28 km/h 0.3 mm High 31
20 Sept 33.6 °C 40 % 31 km/h 0.0 mm High 32
21 Sept 35.0 °C 41 % 24 km/h 0.3 mm High 28
22 Sept 32.8 °C 49 % 35 km/h 0.3 mm High 28
23 Sept after 32.3 °C 47 % 32 km/h 0.4 mm High 30
24 Sept after 34.3 °C 41 % 30 km/h 0.1 mm High 29
25 Sept after 35.7 °C 38 % 28 km/h 0.0 mm High 32
26 Sept after 35.9 °C 38 % 25 km/h 0.0 mm High 28
27 Sept after 34.8 °C 40 % 28 km/h 0.0 mm High 29
28 Sept after 29.9 °C 56 % 32 km/h 4.6 mm Moderate 11

Its twins: fires that started in the same weather

It started with an FWI of 32.5, a minimum humidity of 36% and 51 days without rain. Fires in the area that started in weather like this since 2016: 18.

FWI at the start 32.5
Minimum humidity 36 %
Days without rain 51
this fire chosen twins rest of the area
Almost identicalSimilar

Outlines of the closest twins

São Félix do Xingu fire, August 2022
3,698 ha 25 days FWI 31.3 Min. humidity 36 % 102 km away, in 2022

First rain (1 mm or more) after it ended: 1.4 mm on 13 Sept.

See its page Compare with this fire

What happened to them

25 days
median duration
4,446 ha
median area
28 %
went past 10,000 ha
1.7 mm
rain at the end (median; 6 of 18 had it)

It burned an area similar to its twins (3,644 ha against a median of 4,446 ha) and lasted 19 days, against 25 days.

In 12 of 18, not even 1 mm fell in the ten days after the end: they went out without rain. In the rest, the first rainy day brought a median of 1.7 mm.

This is a bank of analogues: it shows what usually happens, not what will happen. With fewer than 15 twins we give no figures. How we calculate it

How it ended

4.6 mmfirst rain
28 Sept6 days after it ended
48km/h · max. gust

It was considered over on 22 Sept, and on 28 Sept 4.6 mm fell. We do not know whether the rain or the firefighters put it out. Twins with rain when they ended: 6 of 18, with a median of 1.7 mm.

Weather on this page: Open-Meteo.com (CC BY 4.0) · Copernicus Climate Change Service (ERA5)

How a twin is chosen

  • Same area: fires that have already ended, less than 250 km from this one, since 2016.
  • Same start: we compare the FWI on the first day, the minimum humidity that day and the run of days without rain before it. The slider sets how much they may differ.
  • Only pages with final weather data (ERA5 reanalysis) calculated in the same way as this fire’s; agricultural and grass burns and pages with data under review are left out.
  • Fires burning at the same time as this one (a week before or after) are left out: they share the same spell of weather and do not count as a precedent.
  • They are sorted by similarity, and the outlines of the first five are drawn.

How we calculate it

Before and after, from space

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

Before · 28 Aug 2023
After · 29 Sept 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 19 September 2023 the air beside the fire reached 36 µg/m³ of PM2.5. That day averaged 28: 1.9 times the WHO daily guideline (15).

PM2.5 peak36 µg/m³
Days over the guideline10 days
PM1052 µg/m³
Optical depth0.67
3 Sept7 Sept11 Sept15 Sept19 Sept
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 · 236Every 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 Altamira fire last?
According to the heat detections seen by satellite inside the perimeter, it burned from 4 September 2023 to 22 September 2023 (19 days). The perimeter dates it from 5 September 2023 to 16 September 2023.
How much area did it burn?
The perimeter GWIS (Copernicus) rebuilt from heat detections is 3,644 hectares (36.4 km²). It is an estimate: official national figures may differ.
Which municipalities burned?
The fire only entered Altamira (3,665 ha, 0.0 %).
What was the weather like?
During the fire the temperature reached 35.6 °C, humidity dropped to 30 % and gusts hit 48 km/h. The fire danger index (FWI) reached 38, class 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.
How did the fires that started in similar weather in this area end?
Fires less than 250 km away that started since 2016 with a similar FWI, humidity and dry spell: 18. Their median duration was 25 days and their median area 4,446 ha; 28 % went past 10,000 ha. In 12 of 18, not even 1 mm fell in the ten days after the end: they went out without rain. In the rest, the first rainy day brought a median of 1.7 mm.

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 · 2 Changes in area, dates, name, official record or merged pages, compared every night since 24 October 2026.
  1. Last day with fire: 16 September 2023 → 22 September 2023.
  2. Start date: 5 September 2023 → 4 September 2023.

RSS Changes to this page With cross-checks and a citable version

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 5 September 2023 to 16 September 2023. 236 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.