Thoen fire, April 2023 Thoen
The fire started on 3 April 2023 in Thoen, Thailand, and satellites saw it burning for 4 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 1,335 hectares from heat detections, spread across a single municipality.
It is the 113th largest in Lampang Province since 2016 (of 202 with a page). Number 314 in Thailand in 2023, of 500.
The power measured by the satellite is low (10.9 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
- 1,335ha
- GWIS perimeter (Copernicus)
- Duration
- 4days
- 3 Apr 2023 – 6 Apr 2023
- Municipalities hit
- 1
- districts
- Started on
- 3 Apr
- 2023
- Heat detections
- 39
- in a single hotspot: 11 MW
- Danger at start
- 27
- High · FWI index
- Energy released
- 121MW
- 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 5 days without rain (1 mm or more) when it started.
This area had burned before
92% of the perimeter overlaps earlier fires recorded since 2016: 287 ha in 2016, 467 ha in 2017, 337 ha in 2018, 1,049 ha in 2019, 906 ha in 2020, 24 ha in 2021. Part of it burned more than once, so the yearly figures add up to more than the 1,228 ha that had burned before.
- 1,021 ha Thoen fire, February 2019 2,575 ha in total; the hectares shown are those it shares with this fire
- 906 ha Thoen fire, January 2020 2,893 ha in total; the hectares shown are those it shares with this fire
- 249 ha Thoen fire, March 2017 1,583 ha in total; the hectares shown are those it shares with this fire
What happened to each town
-
Thoen where it started1,343 ha reached on 3 Apr0.8 %
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) |
|---|---|---|---|---|---|
| 27 Mar | 36.5 °C | 24 % | 27 km/h | 0.0 mm | High 27 |
| 28 Mar | 36.3 °C | 28 % | 28 km/h | 0.0 mm | High 28 |
| 29 Mar | 35.4 °C | 32 % | 32 km/h | 0.0 mm | High 30 |
| 30 Mar | 36.0 °C | 30 % | 28 km/h | 0.0 mm | High 30 |
| 31 Mar | 36.0 °C | 33 % | 28 km/h | 0.0 mm | High 28 |
| 1 Apr | 35.9 °C | 33 % | 26 km/h | 0.0 mm | High 28 |
| 2 Apr | 36.2 °C | 29 % | 36 km/h | 0.0 mm | High 33 |
| 3 Apr | 35.8 °C | 27 % | 39 km/h | 0.0 mm | High 34 |
| 4 Apr | 36.5 °C | 28 % | 34 km/h | 0.0 mm | High 33 |
| 5 Apr | 36.4 °C | 27 % | 22 km/h | 0.0 mm | High 30 |
| 6 Apr | 36.8 °C | 30 % | 19 km/h | 0.0 mm | High 32 |
| 7 Apr after | 36.5 °C | 34 % | 20 km/h | 0.0 mm | High 31 |
| 8 Apr after | 36.7 °C | 33 % | 20 km/h | 0.0 mm | High 32 |
| 9 Apr after | 35.8 °C | 34 % | 26 km/h | 0.0 mm | High 33 |
| 10 Apr after | 37.3 °C | 31 % | 25 km/h | 0.0 mm | High 30 |
| 11 Apr after | 38.0 °C | 32 % | 22 km/h | 0.0 mm | High 32 |
| 12 Apr after | 37.8 °C | 32 % | 18 km/h | 0.0 mm | High 33 |
| 13 Apr after | 38.0 °C | 32 % | 31 km/h | 0.0 mm | High 35 |
| 14 Apr after | 38.6 °C | 27 % | 20 km/h | 0.0 mm | High 34 |
| 15 Apr after | 38.6 °C | 30 % | 18 km/h | 0.0 mm | High 34 |
| 16 Apr after | 37.6 °C | 30 % | 26 km/h | 0.0 mm | High 34 |
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 6 April 2023 the air beside the fire reached 58 µg/m³ of PM2.5. That day averaged 37: 2.5 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 · 39Every 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 Thoen fire last?
- GWIS (Copernicus) dates it between 3 April 2023 and 6 April 2023: 4 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 1,335 hectares (13.4 km²). It is an estimate: official national figures may differ.
- Which municipalities burned?
- The fire only entered Thoen (1,343 ha, 0.8 %).
- What was the weather like?
- During the fire the temperature reached 36.8 °C, humidity dropped to 24 % and gusts hit 39 km/h. The fire danger index (FWI) reached 34, class High.
- Where does this data come from?
- From the GWIS (Copernicus) burnt perimeter, NASA FIRMS VIIRS hotspots and the administrative boundaries of Thailand (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: 199 · 191
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.