Alor fire, September 2025 Alor
The fire started on 11 September 2025 in Alor, Indonesia, and satellites saw it burning for 6 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 1,781 hectares from heat detections, spread across a single municipality.
It is the 27th largest in East Nusa Tenggara since 2016 (of 40 with a page). Number 37 in Indonesia in 2025, of 48.
The power measured by the satellite is low (14.8 MW in the strongest hotspot), more typical of grass or stubble burning, or a slow surface fire, than of a large crown fire.
- Burnt area
- 1,781ha
- GWIS perimeter (Copernicus)
- Duration
- 6days
- 11 Sept 2025 – 16 Sept 2025
- Municipalities hit
- 1
- regencies
- Started on
- 11 Sept
- 2025
- Heat detections
- 22
- in a single hotspot: 15 MW
- Danger at start
- 8
- Low · FWI index
- Energy released
- 172MW
- sum of detected power
Where it burned
How it evolved, day by day
Fire radiative power detected each day, in megawatts, and number of hotspots. The magenta bar marks the peak day.
The weather it burned in
It had gone one day without rain (1 mm or more) when it started.
This area had burned before
60% of the perimeter overlaps earlier fires recorded since 2016: 301 ha in 2017, 121 ha in 2018, 606 ha in 2019, 267 ha in 2020, 273 ha in 2021, 251 ha in 2022, 331 ha in 2023, 26 ha in 2024. Part of it burned more than once, so the yearly figures add up to more than the 1,068 ha that had burned before.
What happened to each town
-
Alor where it started1,793 ha reached on 11 Sept0.6 %
Burnt area inside each municipality, from crossing the GWIS perimeter with administrative boundaries. The distance is from the town centre 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) |
|---|---|---|---|---|---|
| 11 Sept | 28.0 °C | 65 % | 22 km/h | 0.0 mm | Low 8 |
| 12 Sept | 28.2 °C | 65 % | 20 km/h | 0.0 mm | Low 10 |
| 13 Sept | 28.1 °C | 63 % | 23 km/h | 0.1 mm | Moderate 13 |
| 14 Sept | 28.3 °C | 57 % | 24 km/h | 0.0 mm | Moderate 14 |
| 15 Sept | 27.8 °C | 63 % | 24 km/h | 0.0 mm | Moderate 15 |
| 16 Sept | 27.8 °C | 65 % | 28 km/h | 0.0 mm | Moderate 17 |
| 17 Sept after | 28.3 °C | 62 % | 22 km/h | 0.3 mm | Moderate 13 |
| 18 Sept after | 28.0 °C | 61 % | 27 km/h | 0.0 mm | Moderate 16 |
| 19 Sept after | 27.8 °C | 57 % | 26 km/h | 0.0 mm | Moderate 16 |
| 20 Sept after | 27.7 °C | 64 % | 28 km/h | 0.0 mm | Moderate 18 |
| 21 Sept after | 27.8 °C | 69 % | 35 km/h | 0.0 mm | Moderate 19 |
| 22 Sept after | 28.4 °C | 65 % | 30 km/h | 0.0 mm | Moderate 17 |
| 23 Sept after | 27.7 °C | 69 % | 21 km/h | 0.7 mm | Low 10 |
| 24 Sept after | 29.1 °C | 53 % | 22 km/h | 0.1 mm | Moderate 15 |
| 25 Sept after | 28.3 °C | 62 % | 28 km/h | 0.0 mm | Moderate 16 |
| 26 Sept after | 28.9 °C | 63 % | 28 km/h | 0.6 mm | Moderate 17 |
Before and after, from space
Drag the line to compare the same ground before the fire and after it.
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 · CopernicusOn 16 September 2025 the air beside the fire reached 26 µg/m³ of PM2.5. That day averaged 16: 1.0 times the WHO daily guideline (15).
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 · 22Every satellite heat detection, one by one, with time, satellite, power and coordinates.
| Date and time | Satellite | FRP (MW) | Lat | Lon |
|---|
Other fires nearby
Frequently asked questions
- How long did the Alor fire last?
- GWIS (Copernicus) dates it between 11 September 2025 and 16 September 2025: 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 1,781 hectares (17.8 km²). It is an estimate: official national figures may differ.
- Which municipalities burned?
- The fire only entered Alor (1,793 ha, 0.6 %).
- What was the weather like?
- During the fire the temperature reached 28.3 °C, humidity dropped to 57 % and gusts hit 28 km/h. The fire danger index (FWI) reached 17, class Moderate.
- Where does this data come from?
- From the GWIS (Copernicus) burnt perimeter, NASA FIRMS VIIRS hotspots and the administrative boundaries of Indonesia (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: 112
Satellite cross-check
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
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.