Aso fire, 5 March 2023 阿蘇市 · Aso
The fire started on 5 March 2023 in Aso, Japan, and satellites saw it burning for 1 day. Copernicus’s global GWIS system rebuilt a burnt perimeter of 232 hectares from heat detections, spread across a single municipality.
It is the 79th largest in Kumamoto since 2016 (of 92 with a page). Number 20 in Japan in 2023, of 23.
Compare with…
Suggestions: Aso · 2020Aso · 2016Aso · 2022Aso · 2018
- Burnt area
- 232ha
- GWIS perimeter (Copernicus)
- Duration
- 1day
- 5 Mar 2023 – 5 Mar 2023
- Municipalities hit
- 1
- municipalities
- Started on
- 5 Mar
- 2023
- Heat detections
- 9
- in a single hotspot: 58 MW
- Danger at start
- 1
- Very low · FWI index
- Average daily power
- 315MW
- detected power per day, on average
Where it burned
How it evolved, day by day
5 Mar 2023 · 315 MW · 9
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 0 days without rain (1 mm or more) when it started. Rain came after the fire: 7.6 mm on 12 Mar.
This area had burned before
78% of the perimeter overlaps earlier fires recorded since 2016: 114 ha in 2016, 176 ha in 2020. Part of it burned more than once, so the yearly figures add up to more than the 180 ha that had burned before.
What happened to each town
-
233 ha0.6 %
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 2025Inside 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) |
|---|---|---|---|---|---|
| 5 Mar | 13.4 °C | 33 % | 24 km/h | 0.0 mm | Very low 1 |
| 6 Mar after | 13.7 °C | 34 % | 29 km/h | 0.0 mm | Very low 2 |
| 7 Mar after | 14.9 °C | 34 % | 27 km/h | 0.0 mm | Very low 3 |
| 8 Mar after | 16.5 °C | 33 % | 29 km/h | 0.0 mm | Very low 4 |
| 9 Mar after | 13.0 °C | 67 % | 48 km/h | 0.8 mm | Very low 2 |
| 10 Mar after | 18.5 °C | 48 % | 19 km/h | 0.0 mm | Very low 2 |
| 11 Mar after | 19.6 °C | 45 % | 24 km/h | 0.0 mm | Very low 3 |
| 12 Mar after | 18.5 °C | 43 % | 50 km/h | 7.6 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 5 March 2023 the air beside the fire reached 101 µg/m³ of PM2.5. That day averaged 54: 3.6 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 · 9Every 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 Aso fire last?
- GWIS (Copernicus) dates it between 5 March 2023 and 5 March 2023: 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 232 hectares (2.3 km²). It is an estimate: official national figures may differ.
- Which municipalities burned?
- The fire only entered Aso (233 ha, 0.6 %).
- What was the weather like?
- During the fire the temperature reached 13.4 °C, humidity dropped to 33 % and gusts hit 24 km/h. The fire danger index (FWI) reached 1, 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 · 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.
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. 9 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.
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.