Sop Moei fire, 21 March 2026 สบเมย · Sop Moei, Tha Song Yang, Mae Sariang
The fire started on 21 March 2026 in Sop Moei, Thailand, and satellites saw it burning for 35 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 56,946 hectares from heat detections, spread across 4 municipalities.
It is the 4th largest in Mae Hong Son Province since 2016 (of 387 with a page). Number 6 in Thailand in 2026, of 689.
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- Burnt area
- 56,946ha
- GWIS perimeter (Copernicus)
- Duration
- 35days
- 21 Mar 2026 – 24 Apr 2026
- Municipalities hit
- 4
- districts
- Started on
- 21 Mar
- 2026
- Heat detections
- 1,574
- in a single hotspot: 149 MW
- Danger at start
- 16
- Moderate · FWI index
- Average daily power
- 210MW
- detected power per day, on average
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: 7.9 mm on 25 Apr.
This area had burned before
94% of the perimeter overlaps earlier fires recorded since 2016: 23,721 ha in 2016, 17,052 ha in 2017, 19,701 ha in 2018, 30,152 ha in 2019, 29,222 ha in 2020, 12,958 ha in 2021, 3,520 ha in 2022, 21,338 ha in 2023, 19,089 ha in 2024, 21,646 ha in 2025. Part of it burned more than once, so the yearly figures add up to more than the 53,684 ha that had burned before.
- 10,524 ha Sop Moei fire, March 2019 12,470 ha in total; the hectares shown are those it shares with this fire
- 4,415 ha Sop Moei fire, March 2025 5,505 ha in total; the hectares shown are those it shares with this fire
- 3,597 ha Tha Song Yang fire, March 2020 3,858 ha in total; the hectares shown are those it shares with this fire
- 3,385 ha Sop Moei fire, March 2025 3,833 ha in total; the hectares shown are those it shares with this fire
- 3,238 ha Omkoi fire, March 2017 3,550 ha in total; the hectares shown are those it shares with this fire
- 3,117 ha Sop Moei fire, March 2023 3,128 ha in total; the hectares shown are those it shares with this fire
- 3,003 ha Sop Moei fire, March 2019 4,001 ha in total; the hectares shown are those it shares with this fire
- 2,914 ha Sop Moei fire, March 2025 3,250 ha in total; the hectares shown are those it shares with this fire
How big is it?
London boundary: geoBoundaries · Office for National Statistics (Open Government Licence v3.0).
Bangkok boundary: geoBoundaries · OpenStreetMap, Wambacher · © OpenStreetMap contributors (ODbL 1.0).
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).
This compares size, not location: both shapes are at the same scale, north up, centred on each other.
What happened to each town
-
35,813 ha reached on 21 Mar25 %
-
Tha Song Yang ท่าสองยาง8,425 ha reached on 28 Mar4.3 %
-
Mae Sariang แม่สะเรียง8,094 ha reached on 23 Mar3.1 %
-
Omkoi อมก๋อย4,941 ha reached on 23 Mar1.7 %
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 were about 19 hectares of built-up land and about 3,500 residents (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) |
|---|---|---|---|---|---|
| 21 Mar | 36.0 °C | 40 % | 36 km/h | 0.4 mm | Moderate 16 |
| 22 Mar | 35.4 °C | 44 % | 41 km/h | 0.0 mm | Moderate 18 |
| 23 Mar | 35.8 °C | 35 % | 38 km/h | 0.0 mm | Moderate 19 |
| 24 Mar | 36.1 °C | 33 % | 37 km/h | 0.0 mm | Moderate 20 |
| 25 Mar | 36.3 °C | 33 % | 37 km/h | 0.0 mm | Moderate 21 |
| 26 Mar | 37.4 °C | 31 % | 37 km/h | 0.0 mm | High 23 |
| 27 Mar | 37.1 °C | 34 % | 41 km/h | 0.0 mm | High 25 |
| 28 Mar | 37.0 °C | 39 % | 39 km/h | 0.0 mm | High 25 |
| 29 Mar | 37.2 °C | 36 % | 41 km/h | 0.0 mm | High 26 |
| 30 Mar | 37.6 °C | 36 % | 38 km/h | 0.0 mm | High 26 |
| 31 Mar | 37.1 °C | 42 % | 35 km/h | 0.0 mm | High 24 |
| 1 Apr | 37.5 °C | 39 % | 30 km/h | 0.0 mm | High 25 |
| 2 Apr | 38.3 °C | 36 % | 36 km/h | 0.0 mm | High 27 |
| 3 Apr | 37.8 °C | 39 % | 35 km/h | 0.0 mm | High 27 |
| 4 Apr | 36.3 °C | 46 % | 31 km/h | 0.0 mm | High 24 |
| 5 Apr | 36.3 °C | 48 % | 37 km/h | 0.0 mm | High 24 |
| 6 Apr | 36.1 °C | 49 % | 35 km/h | 0.0 mm | High 24 |
| 7 Apr | 34.5 °C | 56 % | 42 km/h | 1.6 mm | Moderate 12 |
| 8 Apr | 37.2 °C | 38 % | 43 km/h | 0.0 mm | High 25 |
| 9 Apr | 36.2 °C | 39 % | 43 km/h | 0.0 mm | High 26 |
| 10 Apr | 37.2 °C | 39 % | 41 km/h | 0.0 mm | High 26 |
| 11 Apr | 37.0 °C | 36 % | 42 km/h | 0.2 mm | High 28 |
| 12 Apr | 37.3 °C | 41 % | 35 km/h | 0.0 mm | High 27 |
| 13 Apr | 37.4 °C | 44 % | 35 km/h | 0.0 mm | High 28 |
| 14 Apr | 37.9 °C | 41 % | 33 km/h | 0.0 mm | High 28 |
| 15 Apr | 37.4 °C | 36 % | 39 km/h | 0.0 mm | High 30 |
| 16 Apr | 37.8 °C | 41 % | 35 km/h | 0.0 mm | High 29 |
| 17 Apr | 38.4 °C | 38 % | 31 km/h | 0.0 mm | High 29 |
| 18 Apr | 37.9 °C | 45 % | 32 km/h | 0.1 mm | High 29 |
| 19 Apr | 37.1 °C | 42 % | 42 km/h | 0.0 mm | High 31 |
| 20 Apr | 37.0 °C | 43 % | 42 km/h | 0.0 mm | High 31 |
| 21 Apr | 35.8 °C | 56 % | 37 km/h | 1.7 mm | Moderate 13 |
| 22 Apr | 37.6 °C | 46 % | 34 km/h | 0.1 mm | High 22 |
| 23 Apr | 36.8 °C | 53 % | 34 km/h | 1.0 mm | Moderate 17 |
| 24 Apr | 38.0 °C | 48 % | 22 km/h | 0.2 mm | Moderate 21 |
| 25 Apr after | 35.1 °C | 54 % | 29 km/h | 7.9 mm | Very low 4 |
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 3 April 2026 the air beside the fire reached 110 µg/m³ of PM2.5. That day averaged 58: 3.9 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 · 1,574Every 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 Sop Moei fire last?
- According to the heat detections seen by satellite inside the perimeter, it burned from 21 March 2026 to 24 April 2026 (35 days). The perimeter dates it from 22 March 2026 to 22 April 2026.
- How much area did it burn?
- The perimeter GWIS (Copernicus) rebuilt from heat detections is 56,946 hectares (569.5 km²). It is an estimate: official national figures may differ.
- Which municipalities burned?
- The fire entered 4 municipalities: Sop Moei (35,813 ha, 25 %); Tha Song Yang (8,425 ha, 4.3 %); Mae Sariang (8,094 ha, 3.1 %); Omkoi (4,941 ha, 1.7 %).
- What was the weather like?
- During the fire the temperature reached 38.4 °C, humidity dropped to 31 % and gusts hit 43 km/h. The fire danger index (FWI) reached 31, 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 · Emergency number and official warnings ›
Satellite cross-check
History of this page · 2 Changes in area, dates, name, official record or merged pages, compared every night since 24 October 2026.
- Last day with fire: 22 April 2026 → 24 April 2026.
- Start date: 22 March 2026 → 21 March 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; 12 polygons grouped in this page.
- Dates adjusted with the VIIRS detections inside the perimeter, which said 22 March 2026 to 22 April 2026. 1,574 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 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.