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TH · Thailand · –

Sam Ngao fire, 16 March 2025 สามเงา · Sam Ngao

Out · last detection 31 Mar 2025, 19:01 UTC

The fire started on 16 March 2025 in Sam Ngao, Thailand, and satellites saw it burning for 16 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 10,328 hectares from heat detections, spread across a single municipality.

It is the 4th largest in Tak Province since 2016 (of 266 with a page). Number 3 in Thailand in 2025, of 173.

The power measured by the satellite is low (20.2 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
10,328ha
GWIS perimeter (Copernicus)
Duration
16days
16 Mar 2025 – 31 Mar 2025
Municipalities hit
1
districts
Started on
16 Mar
2025
Heat detections
372
in a single hotspot: 20 MW
Danger at start
27
High · FWI index
Average daily power
79MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 16 Mar31 Mar
31 Mar 2025

How it evolved, day by day

16 Mar 2025 · 7 MW · 3 17 Mar 2025 · 39 MW · 9 18 Mar 2025 · 28 MW · 9 19 Mar 2025 · 7 MW · 5 20 Mar 2025 · 8 MW · 5 21 Mar 2025 · 39 MW · 19 22 Mar 2025 · 33 MW · 18 23 Mar 2025 · 31 MW · 15 24 Mar 2025 · 136 MW · 35 25 Mar 2025 · 318 MW · 75 26 Mar 2025 · 224 MW · 76 27 Mar 2025 · 228 MW · 64 28 Mar 2025 · 26 MW · 8 29 Mar 2025 · 79 MW · 13 30 Mar 2025 · 49 MW · 14 31 Mar 2025 · 6 MW · 4
16 Mar 20 Mar 25 Mar 28 Mar

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

The weather it burned in

34°high
36km/h · peak gust
26%lowest humidity

It had gone 20 days without rain (1 mm or more) when it started. Rain came after the fire: 2.2 mm on 1 Apr.

This area had burned before

94% of the perimeter overlaps earlier fires recorded since 2016: 1,598 ha in 2016, 6,958 ha in 2017, 797 ha in 2018, 5,755 ha in 2019, 3,614 ha in 2020, 5,326 ha in 2021, 5,559 ha in 2023, 384 ha in 2024. Part of it burned more than once, so the yearly figures add up to more than the 9,748 ha that had burned before.

How big is it?

10 km
It burned the equivalent of 6.5% of the area of London (103 km² against 1,583 km²).

London boundary: geoBoundaries · Office for National Statistics (Open Government Licence v3.0).

This compares size, not location: both shapes are at the same scale, north up, centred on each other.

What happened to each town

  1. Sam Ngao สามเงา where it started
    10,383 ha reached on 16 Mar
    3.8 %

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 2025
Built-up area< 0.1 ha
Residents< 20

Inside the perimeter there was no noticeable built-up land and almost nobody lived there (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)
16 Mar 34.4 °C 30 % 22 km/h 0.0 mm High 27
17 Mar 34.5 °C 32 % 26 km/h 0.0 mm High 30
18 Mar 33.3 °C 32 % 29 km/h 0.0 mm High 31
19 Mar 28.0 °C 48 % 34 km/h 0.0 mm High 29
20 Mar 28.0 °C 43 % 30 km/h 0.0 mm High 27
21 Mar 29.6 °C 40 % 27 km/h 0.0 mm High 27
22 Mar 30.9 °C 33 % 28 km/h 0.0 mm High 30
23 Mar 33.1 °C 32 % 22 km/h 0.0 mm High 27
24 Mar 34.1 °C 30 % 28 km/h 0.1 mm High 27
25 Mar 34.5 °C 26 % 32 km/h 0.0 mm High 32
26 Mar 34.1 °C 27 % 36 km/h 0.0 mm High 35
27 Mar 33.7 °C 27 % 36 km/h 0.0 mm High 38
28 Mar 32.4 °C 29 % 29 km/h 0.0 mm High 34
29 Mar 34.2 °C 26 % 27 km/h 0.0 mm High 36
30 Mar 33.3 °C 34 % 29 km/h 0.0 mm High 38
31 Mar 31.8 °C 39 % 28 km/h 0.1 mm High 31
1 Apr after 31.4 °C 46 % 31 km/h 2.2 mm High 26

Its twins: fires that started in the same weather

It started with an FWI of 27.3, a minimum humidity of 30% and 20 days without rain. Fires in the area that started in weather like this since 2016: 47.

FWI at the start 27.3
Minimum humidity 30 %
Days without rain 20
this fire chosen twins rest of the area
Almost identicalSimilar

Outlines of the closest twins

Li fire, January 2020
1,411 ha 13 days FWI 27.6 Min. humidity 30 % 13 km away, in 2020

First rain (1 mm or more) after it ended: none in the following ten days.

What happened to them

10 days
median duration
1,412 ha
median area
100 %
went past 1,000 ha
1.7 mm
rain at the end (median; 17 of 47 had it)

It was 7.3 times larger than the median of its twins and lasted 16 days, against 10 days.

Only 1 of its 47 twins burned more. The weather on the first day does not explain everything: the wind in the following days, the fuel and the firefighting also count. In 30 of 47, not even 1 mm fell in the ten days after the end: they went out without rain. In the rest, the first rainy day brought a median of 1.7 mm.

This is a bank of analogues: it shows what usually happens, not what will happen. With fewer than 15 twins we give no figures. How we calculate it

How it ended

2.2 mmfirst rain
1 Aprthe day after it ended
36km/h · max. gust

It was considered over on 31 Mar, and on 1 Apr 2.2 mm fell. We do not know whether the rain or the firefighters put it out. Twins with rain when they ended: 17 of 47, with a median of 1.7 mm.

Weather on this page: Open-Meteo.com (CC BY 4.0) · Copernicus Climate Change Service (ERA5)

How a twin is chosen

  • Same area: fires that have already ended, less than 250 km from this one, since 2016.
  • Same start: we compare the FWI on the first day, the minimum humidity that day and the run of days without rain before it. The slider sets how much they may differ.
  • Only pages with final weather data (ERA5 reanalysis) calculated in the same way as this fire’s; agricultural and grass burns and pages with data under review are left out.
  • Fires burning at the same time as this one (a week before or after) are left out: they share the same spell of weather and do not count as a precedent.
  • They are sorted by similarity, and the outlines of the first five are drawn.

How we calculate it

Before and after, from space

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

Before · 9 Mar 2025
After · 7 Apr 2025

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 29 March 2025 the air beside the fire reached 108 µg/m³ of PM2.5. That day averaged 62: 4.1 times the WHO daily guideline (15).

PM2.5 peak108 µg/m³
Days over the guideline21 days
PM10116 µg/m³
Optical depth1.46
14 Mar19 Mar24 Mar29 Mar3 Apr
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 · 372Every 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 Sam Ngao fire last?
GWIS (Copernicus) dates it between 16 March 2025 and 31 March 2025: 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 10,328 hectares (103.3 km²). It is an estimate: official national figures may differ.
Which municipalities burned?
The fire only entered Sam Ngao (10,383 ha, 3.8 %).
What was the weather like?
During the fire the temperature reached 34.5 °C, humidity dropped to 26 % and gusts hit 36 km/h. The fire danger index (FWI) reached 38, 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.
How did the fires that started in similar weather in this area end?
Fires less than 250 km away that started since 2016 with a similar FWI, humidity and dry spell: 47. Their median duration was 10 days and their median area 1,412 ha; 100 % went past 1,000 ha. Only 1 of its 47 twins burned more. The weather on the first day does not explain everything: the wind in the following days, the fuel and the firefighting also count. In 30 of 47, not even 1 mm fell in the ten days after the end: they went out without rain. In the rest, the first rainy day brought a median of 1.7 mm.

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 Changes in area, dates, name, official record or merged pages, compared every night since 24 October 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
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.

How we know this
  • Perimeter: GWIS (Copernicus), rebuilt from heat detections rather than mapped on imagery; 2 polygons grouped in this page.
  • Dates from the perimeter: the VIIRS detections inside it did not change them. 372 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.

How we build fire pages: methodology

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.