Pai fire, 25 March 2023 Thailand
The fire started on 25 March 2023 in Pai, Thailand, and satellites saw it burning for 2 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 1,582 hectares from heat detections, spread across a single municipality.
It is the 361th largest in Mae Hong Son Province since 2016 (of 668 with a page). Number 241 in Thailand in 2023, of 500.
We have the GWIS perimeter for this fire, but the VIIRS sensors did not capture it in enough detail: no day-by-day evolution, but the split by municipality is there.
- Burnt area
- 1,582ha
- GWIS perimeter (Copernicus)
- Duration
- 2days
- 25 Mar 2023 – 26 Mar 2023
- Municipalities hit
- 0
- districts
- Started on
- 25 Mar
- 2023
- Danger at start
- 25
- High · FWI index
Where it burned
The weather it burned in
It had gone 11 days without rain (1 mm or more) when it started.
This area had burned before
100% of the perimeter overlaps earlier fires recorded since 2016: 845 ha in 2016, 1,396 ha in 2017, 273 ha in 2018, 1,207 ha in 2019, 1,443 ha in 2020, 1,582 ha in 2021. Part of it burned more than once, so the yearly figures add up to more than the 1,589 ha that had burned before.
- 1,414 ha Pai fire, February 2020 11,077 ha in total; the hectares shown are those it shares with this fire
- 1,178 ha Pai fire, March 2017 4,895 ha in total; the hectares shown are those it shares with this fire
- 1,100 ha Pai fire, March 2019 7,758 ha in total; the hectares shown are those it shares with this fire
- 1,003 ha Pang Mapha fire, March 2021 6,089 ha in total; the hectares shown are those it shares with this fire
- 845 ha Pang Mapha fire, March 2016 6,917 ha in total; the hectares shown are those it shares with this fire
- 19 ha Pai fire, April 2018 1,499 ha in total; the hectares shown are those it shares with this fire
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) |
|---|---|---|---|---|---|
| 25 Mar | 33.2 °C | 29 % | 32 km/h | 0.0 mm | High 25 |
| 26 Mar | 34.2 °C | 25 % | 33 km/h | 0.0 mm | High 26 |
| 27 Mar after | 33.9 °C | 31 % | 34 km/h | 0.0 mm | High 28 |
| 28 Mar after | 35.1 °C | 23 % | 45 km/h | 0.0 mm | High 32 |
| 29 Mar after | 34.0 °C | 25 % | 42 km/h | 0.0 mm | High 32 |
| 30 Mar after | 34.7 °C | 26 % | 37 km/h | 0.0 mm | High 31 |
| 31 Mar after | 34.5 °C | 27 % | 36 km/h | 0.1 mm | High 31 |
| 1 Apr after | 34.7 °C | 29 % | 41 km/h | 0.2 mm | High 33 |
| 2 Apr after | 33.6 °C | 31 % | 47 km/h | 0.0 mm | High 35 |
| 3 Apr after | 33.9 °C | 28 % | 47 km/h | 0.0 mm | High 35 |
| 4 Apr after | 34.2 °C | 24 % | 38 km/h | 0.0 mm | High 34 |
| 5 Apr after | 35.6 °C | 22 % | 28 km/h | 0.0 mm | High 32 |
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 29 March 2023 the air beside the fire reached 72 µg/m³ of PM2.5. That day averaged 43: 2.9 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)
Other fires nearby
- 21,035 haMongton16 February 2024 · 30 days · 24 km away
- 21,661 haMongton21 March 2026 · 17 days · 29 km away
- 30,393 haPang Mapha23 March 2026 · 31 days · 30 km away
- 20,728 haMongpan8 March 2019 · 18 days · 36 km away
- 22,763 haPai24 March 2026 · 26 days · 40 km away
- 20,395 haPang Mapha19 March 2026 · 25 days · 40 km away
Frequently asked questions
- How long did the Pai fire last?
- GWIS (Copernicus) dates it between 25 March 2023 and 26 March 2023: 2 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 1,582 hectares (15.8 km²). It is an estimate: official national figures may differ.
- What was the weather like?
- During the fire the temperature reached 34.2 °C, humidity dropped to 25 % and gusts hit 33 km/h. The fire danger index (FWI) reached 26, 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.