Kusu fire, 9 March 2025 Kusu
The fire started on 9 March 2025 in Kusu, Japan, and satellites saw it burning for 1 day. Copernicus’s global GWIS system rebuilt a burnt perimeter of 336 hectares from heat detections, spread across a single municipality.
It is the 10th largest in Oita since 2016 (of 20 with a page). Number 12 in Japan in 2025, of 24.
The power measured by the satellite is low (5.8 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
- 336ha
- GWIS perimeter (Copernicus)
- Duration
- 1day
- 9 Mar 2025 – 9 Mar 2025
- Municipalities hit
- 1
- municipalities
- Started on
- 9 Mar
- 2025
- Heat detections
- 8
- in a single hotspot: 6 MW
- Danger at start
- 0
- Very low · FWI index
- Energy released
- 41MW
- 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 4 days without rain (1 mm or more) when it started. Rain came after the fire: 4.3 mm on 10 Mar.
This area had burned before
99% of the perimeter overlaps earlier fires recorded since 2016: 329 ha in 2019, 143 ha in 2020, 2 ha in 2021, 178 ha in 2022, 237 ha in 2024. Part of it burned more than once, so the yearly figures add up to more than the 333 ha that had burned before.
- 237 ha Kusu fire, March 2024 307 ha in total; the hectares shown are those it shares with this fire
- 204 ha Kusu fire, March 2019 244 ha in total; the hectares shown are those it shares with this fire
- 178 ha Kusu fire, March 2022 363 ha in total; the hectares shown are those it shares with this fire
- 143 ha Kusu fire, March 2020 1,065 ha in total; the hectares shown are those it shares with this fire
- 125 ha Kusu fire, March 2019 821 ha in total; the hectares shown are those it shares with this fire
- 2 ha Kusu fire, March 2021 220 ha in total; the hectares shown are those it shares with this fire
What happened to each town
-
Kusu where it started337 ha1.2 %
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) |
|---|---|---|---|---|---|
| 9 Mar | 10.7 °C | 40 % | 31 km/h | 0.0 mm | Very low 0 |
| 10 Mar after | 13.3 °C | 35 % | 23 km/h | 4.3 mm | Very low 0 |
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 10 March 2025 the air beside the fire reached 147 µg/m³ of PM2.5. That day averaged 52: 3.5 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 · 8Every 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 Kusu fire last?
- GWIS (Copernicus) dates it between 9 March 2025 and 9 March 2025: 1 day 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 336 hectares (3.4 km²). It is an estimate: official national figures may differ.
- Which municipalities burned?
- The fire only entered Kusu (337 ha, 1.2 %).
- What was the weather like?
- During the fire the temperature reached 10.7 °C, humidity dropped to 40 % and gusts hit 31 km/h. The fire danger index (FWI) reached 0, class Very low.
- Where does this data come from?
- From the GWIS (Copernicus) burnt perimeter, NASA FIRMS VIIRS hotspots and the administrative boundaries of Japan (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: 119
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-ShareAlike 2.0). 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.