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AU · Australia · –

West Arnhem fire, 25 September 2023 West Arnhem

Out · last detection 16 Oct 2023, 17:02 UTC

The fire started on 25 September 2023 in West Arnhem, Australia, and satellites saw it burning for 22 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 18,949 hectares from heat detections, spread across a single municipality.

This entry is probably a savanna fire in Australia’s tropical north, not a bushfire like those in the south of the country. Millions of hectares of northern savanna and grassland burn every year: much of it in burns lit on purpose early in the dry season (traditional fire management, parks and cattle stations), the rest in grass fires that return to the same ground every few years. This is our assumption, based on the location; it is not confirmed. That is why it is left out of the wildfire rankings.

Burnt area
18,949ha
GWIS perimeter (Copernicus)
Duration
22days
25 Sept 2023 – 16 Oct 2023
Municipalities hit
1
local government areas
Started on
25 Sept
2023
Heat detections
849
in a single hotspot: 288 MW
Danger at start
47
Very high · FWI index
Average daily power
367MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 25 Sept16 Oct
16 Oct 2023

How it evolved, day by day

25 Sept 2023 · 5 MW · 4 26 Sept 2023 · 766 MW · 88 27 Sept 2023 · 1,501 MW · 120 28 Sept 2023 · 1,000 MW · 67 29 Sept 2023 · 187 MW · 29 30 Sept 2023 · 357 MW · 34 1 Oct 2023 · 1,105 MW · 91 2 Oct 2023 · 656 MW · 113 3 Oct 2023 · 357 MW · 48 4 Oct 2023 · 191 MW · 27 5 Oct 2023 · 17 MW · 7 6 Oct 2023 · 299 MW · 41 7 Oct 2023 · 147 MW · 32 8 Oct 2023 · 55 MW · 8 9 Oct 2023 · 192 MW · 26 10 Oct 2023 · 421 MW · 38 11 Oct 2023 · 259 MW · 35 12 Oct 2023 · 113 MW · 25 13 Oct 2023 · 45 MW · 9 14 Oct 2023 · 33 MW · 5 16 Oct 2023 · 6 MW · 2
27 Sept 5 Oct 10 Oct 16 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

39°high
42km/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

98% of the perimeter overlaps earlier fires recorded since 2016: 835 ha in 2016, 13,928 ha in 2017, 9,605 ha in 2018, 8,872 ha in 2019, 5,968 ha in 2020, 2,219 ha in 2021, 8,089 ha in 2022. Part of it burned more than once, so the yearly figures add up to more than the 18,539 ha that had burned before.

How big is it?

10 km
It burned the equivalent of 12% of the area of London (189 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. West Arnhem where it started
    19,074 ha reached on 25 Sept
    0.4 %

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.

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)

Started with 60 days without rain: 7.6 % of the area in Australia

Day High Min. humidity Peak gust Rain Danger (FWI)
25 Sept 36.4 °C 22 % 35 km/h 0.0 mm Very high 47
26 Sept 36.2 °C 22 % 35 km/h 0.0 mm Very high 44
27 Sept 36.5 °C 23 % 37 km/h 0.0 mm Very high 47
28 Sept 36.8 °C 23 % 41 km/h 0.0 mm Very high 49
29 Sept 35.5 °C 28 % 42 km/h 0.0 mm Very high 45
30 Sept 36.4 °C 24 % 34 km/h 0.0 mm Very high 46
1 Oct 37.2 °C 25 % 35 km/h 0.0 mm Very high 46
2 Oct 37.6 °C 27 % 36 km/h 0.0 mm Very high 47
3 Oct 36.5 °C 29 % 35 km/h 0.0 mm Very high 47
4 Oct 36.7 °C 31 % 32 km/h 0.0 mm Very high 43
5 Oct 35.2 °C 33 % 39 km/h 0.1 mm Very high 40
6 Oct 37.7 °C 25 % 41 km/h 0.0 mm Very high 44
7 Oct 37.2 °C 22 % 38 km/h 0.0 mm Very high 44
8 Oct 37.7 °C 23 % 37 km/h 0.0 mm Very high 46
9 Oct 36.4 °C 28 % 31 km/h 0.0 mm Very high 43
10 Oct 37.2 °C 26 % 35 km/h 0.0 mm Very high 46
11 Oct 37.5 °C 24 % 37 km/h 0.0 mm Very high 46
12 Oct 38.6 °C 22 % 34 km/h 0.0 mm Very high 47
13 Oct 39.0 °C 22 % 34 km/h 0.0 mm Very high 44
14 Oct 38.2 °C 19 % 42 km/h 0.0 mm Very high 50
15 Oct 39.2 °C 15 % 35 km/h 0.0 mm Extreme 52
16 Oct 38.3 °C 19 % 36 km/h 0.0 mm Extreme 54
17 Oct after 38.2 °C 20 % 34 km/h 0.0 mm Extreme 52
18 Oct after 39.6 °C 13 % 35 km/h 0.0 mm Extreme 55
19 Oct after 38.6 °C 20 % 38 km/h 0.0 mm Extreme 58
20 Oct after 37.4 °C 28 % 35 km/h 0.0 mm Extreme 50
21 Oct after 37.3 °C 28 % 32 km/h 0.0 mm Very high 46
22 Oct after 38.0 °C 22 % 34 km/h 0.0 mm Very high 46
23 Oct after 39.1 °C 19 % 34 km/h 0.0 mm Extreme 51
24 Oct after 39.6 °C 19 % 33 km/h 0.0 mm Extreme 50
25 Oct after 40.0 °C 18 % 35 km/h 0.0 mm Extreme 52
26 Oct after 40.7 °C 17 % 34 km/h 0.0 mm Extreme 54

Before and after, from space

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

Before · 18 Sept 2023
After · 23 Oct 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 7 October 2023 the air beside the fire reached 28 µg/m³ of PM2.5, but no daily average passed the WHO guideline (15).

PM2.5 peak28 µg/m³
Days over the guideline0 days
PM1041 µg/m³
Optical depth0.60
23 Sept28 Sept3 Oct8 Oct13 Oct
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 · 849Every 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 Australia

Frequently asked questions

How long did the West Arnhem fire last?
According to the heat detections seen by satellite inside the perimeter, it burned from 25 September 2023 to 16 October 2023 (22 days). The perimeter dates it from 25 September 2023 to 14 October 2023.
How much area did it burn?
The perimeter GWIS (Copernicus) rebuilt from heat detections is 18,949 hectares (189.5 km²). It is an estimate: official national figures may differ.
Which municipalities burned?
The fire only entered West Arnhem (19,074 ha, 0.4 %).
What was the weather like?
During the fire the temperature reached 39.2 °C, humidity dropped to 15 % and gusts hit 42 km/h. The fire danger index (FWI) reached 54, class Extreme.
Where does this data come from?
From the GWIS (Copernicus) burnt perimeter, NASA FIRMS VIIRS hotspots and the administrative boundaries of Australia (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: 000 · 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: 14 October 2023 → 16 October 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 000.

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 25 September 2023 to 14 October 2023. 849 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.
  • Probably a vegetation burn: not counted in the totals.

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 4.0 International (CC BY 4.0)). 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.