Lan Sak fire, 5 April 2026 Lan Sak, Huai Khot
The fire started on 5 April 2026 in Lan Sak, Thailand, and satellites saw it burning for 16 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 2,903 hectares from heat detections, spread across 2 municipalities.
It is the 18th largest in Uthai Thani Province since 2016 (of 72 with a page). Number 251 in Thailand in 2026, of 880.
- Burnt area
- 2,903ha
- GWIS perimeter (Copernicus)
- Duration
- 16days
- 5 Apr 2026 – 20 Apr 2026
- Municipalities hit
- 2
- districts
- Started on
- 5 Apr
- 2026
- Heat detections
- 77
- in a single hotspot: 40 MW
- Danger at start
- 24
- High · FWI index
- Energy released
- 708MW
- 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 14 days without rain (1 mm or more) when it started. Rain came after the fire: 2.8 mm on 25 Apr.
This area had burned before
98% of the perimeter overlaps earlier fires recorded since 2016: 967 ha in 2016, 210 ha in 2017, 988 ha in 2019, 1,721 ha in 2020, 159 ha in 2021, 1,796 ha in 2023, 1,681 ha in 2024, 543 ha in 2025. Part of it burned more than once, so the yearly figures add up to more than the 2,837 ha that had burned before.
- 1,208 ha Lan Sak fire, February 2020 6,174 ha in total; the hectares shown are those it shares with this fire
- 994 ha Lan Sak fire, March 2024 1,096 ha in total; the hectares shown are those it shares with this fire
- 355 ha Lan Sak fire, February 2025 1,030 ha in total; the hectares shown are those it shares with this fire
- 160 ha Huai Khot fire, April 2024 1,437 ha in total; the hectares shown are those it shares with this fire
- 20 ha Huai Khot fire, April 2023 1,313 ha in total; the hectares shown are those it shares with this fire
What happened to each town
-
Lan Sak where it started2,903 ha reached on 2 Apr2.0 %
-
15 ha0.0 %
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) |
|---|---|---|---|---|---|
| 2 Apr | 37.5 °C | 33 % | 25 km/h | 0.0 mm | High 24 |
| 3 Apr | 37.9 °C | 32 % | 20 km/h | 0.0 mm | High 24 |
| 4 Apr | 37.0 °C | 33 % | 21 km/h | 0.0 mm | High 25 |
| 5 Apr | 37.7 °C | 32 % | 22 km/h | 0.0 mm | High 26 |
| 6 Apr | 37.6 °C | 33 % | 20 km/h | 0.0 mm | High 26 |
| 7 Apr | 37.8 °C | 33 % | 20 km/h | 0.0 mm | High 27 |
| 8 Apr | 38.0 °C | 30 % | 18 km/h | 0.0 mm | High 27 |
| 9 Apr | 37.7 °C | 30 % | 20 km/h | 0.0 mm | High 29 |
| 10 Apr | 38.2 °C | 26 % | 21 km/h | 0.0 mm | High 32 |
| 11 Apr | 38.0 °C | 33 % | 26 km/h | 0.0 mm | High 32 |
| 12 Apr | 37.8 °C | 29 % | 19 km/h | 0.0 mm | High 33 |
| 13 Apr | 38.0 °C | 27 % | 19 km/h | 0.0 mm | High 32 |
| 14 Apr | 38.8 °C | 26 % | 24 km/h | 0.0 mm | High 34 |
| 15 Apr | 38.5 °C | 29 % | 25 km/h | 0.0 mm | High 34 |
| 16 Apr | 38.7 °C | 28 % | 23 km/h | 0.0 mm | High 35 |
| 17 Apr | 37.8 °C | 29 % | 22 km/h | 0.0 mm | High 35 |
| 18 Apr | 37.5 °C | 31 % | 21 km/h | 0.0 mm | High 34 |
| 19 Apr | 37.3 °C | 34 % | 19 km/h | 0.0 mm | High 32 |
| 20 Apr | 38.5 °C | 28 % | 19 km/h | 0.0 mm | High 35 |
| 21 Apr after | 37.7 °C | 33 % | 24 km/h | 0.0 mm | High 37 |
| 22 Apr after | 37.5 °C | 36 % | 18 km/h | 0.0 mm | High 34 |
| 23 Apr after | 37.4 °C | 35 % | 20 km/h | 0.1 mm | High 34 |
| 24 Apr after | 35.9 °C | 45 % | 21 km/h | 0.9 mm | High 23 |
| 25 Apr after | 32.1 °C | 61 % | 28 km/h | 2.8 mm | Low 6 |
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 12 April 2026 the air beside the fire reached 108 µg/m³ of PM2.5. That day averaged 56: 3.7 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 · 77Every satellite heat detection, one by one, with time, satellite, power and coordinates.
| Date and time | Satellite | FRP (MW) | Lat | Lon |
|---|
Other fires nearby
- 82,117 haBan Rai3 February 2016 · 52 days · 25 km away
- 20,476 haLan Sak3 March 2019 · 15 days · 30 km away
- 57,928 haMae Poen25 March 2026 · 29 days · 34 km away
- 18,076 haBan RaiMarch 2026 · 23 days · 37 km away
- 65,377 haBan Rai4 March 2020 · 41 days · 40 km away
- 25,621 haDan Chang2 April 2026 · 15 days · 40 km away
Frequently asked questions
- How long did the Lan Sak fire last?
- GWIS (Copernicus) dates it between 5 April 2026 and 20 April 2026: 16 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 2,903 hectares (29.0 km²). It is an estimate: official national figures may differ.
- Which municipalities burned?
- The fire entered 2 municipalities: Lan Sak (2,903 ha, 2.0 %); Huai Khot (15 ha, 0.0 %).
- What was the weather like?
- During the fire the temperature reached 38.8 °C, humidity dropped to 26 % and gusts hit 26 km/h. The fire danger index (FWI) reached 35, 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.