Burned area
satellite only6,545ha
Perimeter published by GWIS (Copernicus).
- Source
- GWIS (Copernicus)
- Date
- 21 Sept 2021 – 27 Sept 2021
+− cross-check
No official record is matched to this page to compare it with.
AU · Australia · –
West Arnhem fire, 21 September 2021 West Arnhem
Out · last detection 27 Sept 2021, 04:59 UTC
The fire started on 21 September 2021 in West Arnhem, Australia, and satellites saw it burning for 7 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 6,545 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.
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Fire page data · version 2026-10-24matches the official recordwith caveatssatellite onlymodel
When copying, the sentence is
Tick the figures you want: they make up the lede and the CSV.
Duration by satellite
satellite only7days
21 Sept 2021 to 27 Sept 2021: first and last day with fire on the page.
- Source
- GWIS (Copernicus) · NASA FIRMS · VIIRS
- Date
- last detection: 27 Sept 2021, 04:59 UTC
+− cross-check
Satellites pass a few times a day and cloud or smoke can hide the fire: a lack of detections is not an official extinction. Each country’s emergency service declares a fire contained or out.
Start
satellite only21 Sept 2021
First day with fire seen by the satellites or the perimeter.
- Source
- GWIS (Copernicus) · NASA FIRMS · VIIRS
- Date
- 21 Sept 2021
+− cross-check
No official record is matched to this page, so the alert time and the cause are not known here.
Hotspots
satellite only207
VIIRS detections at 375 m. Most intense hotspot: 42 MW.
- Source
- NASA FIRMS · VIIRS (Suomi NPP)
- Date
- 21 Sept 2021 – 27 Sept 2021
+− cross-check
There is no official record to compare with. Each hotspot is a pixel detected in one satellite pass, not a separate fire.
The worst day
satellite only551MW
Total radiative power on 22 September 2021; hotspots that day: 83.
- Source
- NASA FIRMS · VIIRS (FRP)
- Date
- 22 Sept 2021
+− cross-check
Fire radiative power (FRP) measures the energy the fire gives off when the satellite passes. Added up by day, it compares intensity, not area.
Danger at the start
model63.1FWI · extreme
Fire Weather Index (Canadian system) computed by WorldFires for the day the fire started. Consecutive days without rain before: 60.
- Source
- WorldFires calculation (Canadian FWI system)
- Date
- 21 Sept 2021, local noon
- Model
- ERA5 0,25° (ECMWF · Copernicus C3S) · Open-Meteo.com
+− cross-check
This is an index computed from weather model data, not a measurement of the fire nor an official warning. Danger warnings are issued by each country’s authority. Emergency number and official warnings
Weather during the fire
model36.1°C · 25% RH
High of 36.1 °C and minimum humidity of 25% on 26 September 2021; gusts of 64 km/h on 21 September 2021.
- Source
- weather model at the fire’s grid cell
- Date
- 21 Sept 2021 – 27 Sept 2021
- Model
- ERA5 0,25° (ECMWF · Copernicus C3S) · Open-Meteo.com
+− cross-check
These are model values for a cell of about 25 km, not from a weather station: they may differ from what was measured on the ground.
This page’s change log has been kept since 24 October 2026: every night what it publishes is compared and the difference is logged. Anything earlier is reconstructed from each source’s date and marked as reconstructed.
Show
-
· reconstructed GHSLPopulation and built-up area computed
-
· reconstructed weatherWeather and FWI computed from the ERA5 reanalysis
What was saved on 24 October 2026
Every night a snapshot of what the page shows is saved. If anything changes, it appears in the list as a log entry.
- Area
- 6,545 ha
- Dates
- 21 Sept 2021 – 27 Sept 2021
- Name
- West Arnhem
- Official record
- —
Versioned permanent link
https://worldfires.org/en/fire/west-arnhem-2021-09-2?v=2026-10-24A version keeps the area, dates, name and official record; the area as it was logged (changes under 2% are not logged). The map, hotspots and weather always show today’s data.
Citation
A lede of about 60 words figures only, no adjectives
CSV for this fire west-arnhem-2021-09-2.csv · daily, no individual hotspots
| fecha | focos_viirs | frp_mw | tmax_c | tmin_c | hr_min_pct | viento_max_kmh | racha_max_kmh | precip_mm | fwi | clase_fwi | dentro_del_incendio |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 2021-09-21 | 42 | 278 | 35.8 | 20.5 | 19 | 29.8 | 64.4 | 0 | 63.1 | extremo | 1 |
| 2021-09-22 | 83 | 551 | 33 | 21.4 | 18 | 26.3 | 57.6 | 0 | 58.6 | extremo | 1 |
| 2021-09-23 | 37 | 195 | 33.7 | 16.9 | 22 | 19.5 | 44.6 | 0 | 50.5 | extremo | 1 |
| 2021-09-24 | 21 | 128 | 34.4 | 19.4 | 26 | 18.7 | 39.2 | 0 | 49 | muy_alto | 1 |
| 2021-09-25 | 15 | 108 | 35.3 | 19.3 | 22 | 18.2 | 40.3 | 0 | 48.7 | muy_alto | 1 |
| 2021-09-26 | 7 | 68 | 36.1 | 19.6 | 25 | 18.8 | 40.3 | 0 | 49.6 | muy_alto | 1 |
| 2021-09-27 | 2 | 8 | 35.8 | 21.5 | 32 | 16.6 | 36.4 | 0 | 43.6 | muy_alto | 1 |
| 2021-09-28 | 0 | 0 | 34.9 | 22.8 | 36 | 16.5 | 36.7 | 0 | 40.2 | muy_alto | 0 |
| 2021-09-29 | 0 | 0 | 35.3 | 21.6 | 34 | 15.3 | 35.3 | 0.1 | 39.2 | muy_alto | 0 |
| 2021-09-30 | 0 | 0 | 35.9 | 24.1 | 33 | 16.9 | 36 | 0 | 41 | muy_alto | 0 |
| 2021-10-01 | 0 | 0 | 36.2 | 22.7 | 32 | 20.6 | 45 | 0 | 44.9 | muy_alto | 0 |
| 2021-10-02 | 0 | 0 | 35.3 | 24.1 | 35 | 18.4 | 38.9 | 0 | 42.6 | muy_alto | 0 |
| 2021-10-03 | 0 | 0 | 36.8 | 23.8 | 40 | 15.1 | 36.4 | 4.4 | 14.2 | moderado | 0 |
It is generated in your browser from this page’s data: one file per fire, aggregated by day and without individual hotspots.
Live widget for your story
It updates itself while the fire is still active and links to this page. Free, with the attribution shown at the bottom.
Sources for this page: GWIS (Copernicus), NASA FIRMS (VIIRS), ERA5 (ECMWF/Copernicus C3S) · Open-Meteo.com (CC BY 4.0), GHSL (JRC). Open-Meteo.com · How we build fire pages: methodology
- Burnt area
- 6,545ha
- GWIS perimeter (Copernicus)
- Duration
- 7days
- 21 Sept 2021 – 27 Sept 2021
- Municipalities hit
- 1
- local government areas
- Started on
- 21 Sept
- 2021
- Heat detections
- 207
- in a single hotspot: 42 MW
- Danger at start
- 63
- Extreme · FWI index
- Average daily power
- 191MW
- detected power per day, on average
Where it burned
HOTSPOTS BY DAY
21 Sept27 Sept
27 Sept 2021
How it evolved, day by day
22 Sept
25 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
36°high
64km/h · peak gust
18%lowest humidity
It had gone more than two months without rain (1 mm or more) when it started. Rain came after the fire: 4.4 mm on 3 Oct.
This area had burned before
91% of the perimeter overlaps earlier fires recorded since 2016: 3,506 ha in 2016, 975 ha in 2017, 4,002 ha in 2018, 1,055 ha in 2019, 1,479 ha in 2020. Part of it burned more than once, so the yearly figures add up to more than the 5,963 ha that had burned before.
How big is it?
London boundary: geoBoundaries · Office for National Statistics (Open Government Licence v3.0).
Paris boundary: geoBoundaries · Institut national de l'information géographique et forestière (IGN-F) (Etalab Open License 2.0).
Madrid boundary: geoBoundaries · Open Data ESRI, IGN Central Registry of Cartography Area (CC BY 4.0).
Berlin boundary: geoBoundaries · Federal Agency for Cartography and Geodesy (dl-de/by-2-0).
This compares size, not location: both shapes are at the same scale, north up, centred on each other.
What happened to each town
-
West Arnhem where it started6,590 ha reached on 21 Sept0.1 %
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 2020Built-up area< 0.1 ha
Residents< 20
Inside the perimeter there was no noticeable built-up land and almost nobody lived there (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)
Started with Strong wind: 44 % of the area in Australia 60 days without rain: 7.6 % of the area in Australia
| Day | High | Min. humidity | Peak gust | Rain | Danger (FWI) |
|---|---|---|---|---|---|
| 21 Sept | 35.8 °C | 19 % | 64 km/h | 0.0 mm | Extreme 63 |
| 22 Sept | 33.0 °C | 18 % | 58 km/h | 0.0 mm | Extreme 59 |
| 23 Sept | 33.7 °C | 22 % | 45 km/h | 0.0 mm | Extreme 50 |
| 24 Sept | 34.4 °C | 26 % | 39 km/h | 0.0 mm | Very high 49 |
| 25 Sept | 35.3 °C | 22 % | 40 km/h | 0.0 mm | Very high 49 |
| 26 Sept | 36.1 °C | 25 % | 40 km/h | 0.0 mm | Very high 50 |
| 27 Sept | 35.8 °C | 32 % | 36 km/h | 0.0 mm | Very high 44 |
| 28 Sept after | 34.9 °C | 36 % | 37 km/h | 0.0 mm | Very high 40 |
| 29 Sept after | 35.3 °C | 34 % | 35 km/h | 0.1 mm | Very high 39 |
| 30 Sept after | 35.9 °C | 33 % | 36 km/h | 0.0 mm | Very high 41 |
| 1 Oct after | 36.2 °C | 32 % | 45 km/h | 0.0 mm | Very high 45 |
| 2 Oct after | 35.3 °C | 35 % | 39 km/h | 0.0 mm | Very high 43 |
| 3 Oct after | 36.8 °C | 40 % | 36 km/h | 4.4 mm | Moderate 14 |
Before and after, from space
Drag the line to compare the same ground before the fire and after it.
↔
Before · 14 Sept 2021
After · 4 Oct 2021
Sentinel-2 did not pass over on that day. Try another date, or use false colour, which is daily.
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 · 207Every 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
Frequently asked questions
- How long did the West Arnhem fire last?
- GWIS (Copernicus) dates it between 21 September 2021 and 27 September 2021: 7 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 6,545 hectares (65.4 km²). It is an estimate: official national figures may differ.
- Which municipalities burned?
- The fire only entered West Arnhem (6,590 ha, 0.1 %).
- What was the weather like?
- During the fire the temperature reached 36.1 °C, humidity dropped to 18 % and gusts hit 64 km/h. The fire danger index (FWI) reached 63, 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 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 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
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. 207 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.
- Probably a vegetation burn: not counted in the totals.
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.