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Pai fire, 17 February 2024 Pai

Out · last detection 18 Mar 2024, 18:48 UTC

The fire started on 17 February 2024 in Pai, Thailand, and satellites saw it burning for 31 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 7,308 hectares from heat detections, spread across a single municipality.

It is the 37th largest in Mae Hong Son Province since 2016 (of 668 with a page). Number 9 in Thailand in 2024, of 350.

The power measured by the satellite is low (24.8 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
7,308ha
GWIS perimeter (Copernicus)
Duration
31days
17 Feb 2024 – 18 Mar 2024
Municipalities hit
1
districts
Started on
17 Feb
2024
Heat detections
336
in a single hotspot: 25 MW
Danger at start
23
High · FWI index
Energy released
1.1GW
sum of detected power

Where it burned

18 Mar 2024
HOTSPOTS BY DAY 17 Feb18 Mar

How it evolved, day by day

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Fire radiative power detected each day, in megawatts, and number of hotspots. The magenta bar marks the peak day.

The weather it burned in

38°high
50km/h · peak gust
20%lowest humidity

It had gone 16 days without rain (1 mm or more) when it started. Rain came after the fire: 5.3 mm on 21 Mar.

This area had burned before

92% of the perimeter overlaps earlier fires recorded since 2016: 1,783 ha in 2016, 4,091 ha in 2017, 1,161 ha in 2018, 2,381 ha in 2019, 4,362 ha in 2020, 1,488 ha in 2021, 1,567 ha in 2022, 2,754 ha in 2023. Part of it burned more than once, so the yearly figures add up to more than the 6,746 ha that had burned before.

What happened to each town

  1. Pai where it started
    7,339 ha reached on 13 Feb
    3.2 %

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)
12 Feb 33.6 °C 37 % 30 km/h 0.0 mm High 23
13 Feb 34.8 °C 28 % 31 km/h 0.0 mm High 28
14 Feb 34.9 °C 25 % 32 km/h 0.0 mm High 30
15 Feb 35.9 °C 25 % 24 km/h 0.0 mm High 30
16 Feb 35.7 °C 29 % 34 km/h 0.0 mm High 32
17 Feb 34.4 °C 28 % 45 km/h 0.0 mm High 36
18 Feb 34.7 °C 25 % 46 km/h 0.0 mm High 36
19 Feb 34.8 °C 24 % 45 km/h 0.0 mm High 36
20 Feb 34.3 °C 22 % 43 km/h 0.0 mm High 37
21 Feb 33.8 °C 29 % 28 km/h 0.0 mm High 32
22 Feb 35.3 °C 28 % 25 km/h 0.0 mm High 32
23 Feb 35.5 °C 28 % 33 km/h 0.0 mm High 35
24 Feb 36.5 °C 22 % 37 km/h 0.0 mm High 37
25 Feb 37.4 °C 20 % 37 km/h 0.0 mm Very high 39
26 Feb 37.9 °C 22 % 28 km/h 0.0 mm High 36
27 Feb 37.9 °C 27 % 35 km/h 0.0 mm Very high 39
28 Feb 37.2 °C 25 % 44 km/h 0.0 mm Very high 42
29 Feb 37.2 °C 25 % 38 km/h 0.0 mm Very high 41
1 Mar 36.7 °C 26 % 40 km/h 0.0 mm Very high 42
2 Mar 37.7 °C 21 % 41 km/h 0.0 mm Very high 43
3 Mar 35.7 °C 33 % 45 km/h 0.0 mm Very high 39
4 Mar 37.2 °C 24 % 37 km/h 0.0 mm High 37
5 Mar 36.8 °C 28 % 35 km/h 0.0 mm High 37
6 Mar 37.5 °C 26 % 31 km/h 0.0 mm High 36
7 Mar 37.2 °C 31 % 24 km/h 0.0 mm High 34
8 Mar 37.8 °C 30 % 41 km/h 0.0 mm Very high 40
9 Mar 38.0 °C 24 % 42 km/h 0.0 mm Very high 40
10 Mar 37.4 °C 29 % 42 km/h 0.0 mm Very high 40
11 Mar 38.0 °C 25 % 34 km/h 0.0 mm Very high 38
12 Mar 36.5 °C 30 % 50 km/h 0.0 mm Very high 43
13 Mar 37.3 °C 24 % 37 km/h 0.0 mm Very high 40
14 Mar 36.2 °C 26 % 33 km/h 0.0 mm Very high 38
15 Mar 36.9 °C 30 % 27 km/h 0.0 mm High 36
16 Mar 37.9 °C 31 % 38 km/h 0.0 mm Very high 40
17 Mar 37.3 °C 33 % 39 km/h 0.0 mm Very high 39
18 Mar 38.4 °C 31 % 33 km/h 0.0 mm High 37
19 Mar after 38.2 °C 29 % 26 km/h 0.1 mm High 35
20 Mar after 33.8 °C 44 % 34 km/h 0.0 mm High 29
21 Mar after 35.6 °C 35 % 27 km/h 5.3 mm Low 8

Before and after, from space

Drag the line to compare the same ground before the fire and after it.

Before · 10 Feb 2024
After · 25 Mar 2024

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 · Copernicus

On 19 March 2024 the air beside the fire reached 51 µg/m³ of PM2.5. That day averaged 39: 2.6 times the WHO daily guideline (15).

PM2.5 peak51 µg/m³
Days over the guideline16 days
PM1079 µg/m³
Optical depth1.90
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Good Fair Moderate Poor Very poor Extremely poor

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 · 336Every satellite heat detection, one by one, with time, satellite, power and coordinates.
⬇ Download CSV Times in UTC. Each detection is a 375 m pixel: a large fire yields hundreds per pass.
Date and timeSatelliteFRP (MW)LatLon

Other fires nearby

All fires in Thailand ›

Frequently asked questions

How long did the Pai fire last?
GWIS (Copernicus) dates it between 17 February 2024 and 18 March 2024: 31 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 7,308 hectares (73.1 km²). It is an estimate: official national figures may differ.
Which municipalities burned?
The fire only entered Pai (7,339 ha, 3.2 %).
What was the weather like?
During the fire the temperature reached 38.4 °C, humidity dropped to 20 % and gusts hit 50 km/h. The fire danger index (FWI) reached 43, class Very 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
What do you think is wrong?

We will only use your email to reply about this report. Privacy. This is not an emergency service: if there is a fire now, call 199 · 191.

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.