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Sam Ngao fire, 10 February 2021 สามเงา · Sam Ngao

Out · last detection 27 Feb 2021, 18:54 UTC

The fire started on 10 February 2021 in Sam Ngao, Thailand, and satellites saw it burning for 18 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 2,642 hectares from heat detections, spread across a single municipality.

It is the 53th largest in Tak Province since 2016 (of 266 with a page). Number 31 in Thailand in 2021, of 187.

The power measured by the satellite is low (7.6 MW in the strongest hotspot), more typical of grass or stubble burning, or a slow surface fire, than of a large crown fire.

Compare with…
Burnt area
2,642ha
GWIS perimeter (Copernicus)
Duration
18days
10 Feb 2021 – 27 Feb 2021
Municipalities hit
1
districts
Started on
10 Feb
2021
Heat detections
79
in a single hotspot: 8 MW
Danger at start
22
High · FWI index
Average daily power
12MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 10 Feb27 Feb
27 Feb 2021

How it evolved, day by day

10 Feb 2021 · 2 MW · 3 11 Feb 2021 · 8 MW · 5 12 Feb 2021 · 4 MW · 3 13 Feb 2021 · 17 MW · 10 14 Feb 2021 · 35 MW · 6 15 Feb 2021 · 26 MW · 8 16 Feb 2021 · 3 MW · 4 17 Feb 2021 · 3 MW · 2 18 Feb 2021 · 8 MW · 3 20 Feb 2021 · 2 MW · 1 21 Feb 2021 · 46 MW · 25 22 Feb 2021 · 13 MW · 4 25 Feb 2021 · 4 MW · 1 27 Feb 2021 · 3 MW · 4
10 Feb 13 Feb 16 Feb 21 Feb

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
45km/h · peak gust
23%lowest humidity

It had gone one day without rain (1 mm or more) when it started.

This area had burned before

86% of the perimeter overlaps earlier fires recorded since 2016: 280 ha in 2016, 1,888 ha in 2017, 799 ha in 2018, 212 ha in 2019, 737 ha in 2020. Part of it burned more than once, so the yearly figures add up to more than the 2,268 ha that had burned before.

How big is it?

10 km
It burned the equivalent of 1.7% of the area of London (26 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
    2,670 ha reached on 10 Feb
    1.0 %

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 2020
Built-up area< 0.1 ha
Residents< 20

Inside the perimeter there was no noticeable built-up land and almost nobody lived there (GHSL 2020, 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.

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)
10 Feb 29.4 °C 32 % 33 km/h 0.0 mm High 22
11 Feb 31.3 °C 29 % 21 km/h 0.0 mm High 24
12 Feb 32.1 °C 29 % 21 km/h 0.0 mm High 26
13 Feb 31.8 °C 28 % 27 km/h 0.0 mm High 27
14 Feb 32.4 °C 27 % 25 km/h 0.0 mm High 27
15 Feb 31.7 °C 27 % 37 km/h 0.0 mm High 30
16 Feb 33.0 °C 30 % 27 km/h 0.0 mm High 28
17 Feb 30.5 °C 49 % 36 km/h 0.8 mm Moderate 18
18 Feb 30.2 °C 40 % 43 km/h 0.0 mm High 24
19 Feb 29.0 °C 38 % 45 km/h 0.0 mm High 26
20 Feb 30.2 °C 39 % 35 km/h 0.0 mm High 23
21 Feb 32.5 °C 33 % 24 km/h 0.0 mm High 26
22 Feb 33.3 °C 34 % 19 km/h 0.0 mm High 24
23 Feb 31.8 °C 46 % 22 km/h 0.0 mm High 24
24 Feb 32.4 °C 42 % 40 km/h 0.0 mm High 27
25 Feb 32.9 °C 35 % 40 km/h 0.0 mm High 29
26 Feb 34.2 °C 28 % 39 km/h 0.0 mm High 33
27 Feb 33.4 °C 23 % 40 km/h 0.0 mm High 36
28 Feb after 33.3 °C 24 % 38 km/h 0.0 mm High 36
1 Mar after 34.6 °C 19 % 29 km/h 0.0 mm High 37
2 Mar after 35.0 °C 27 % 25 km/h 0.0 mm High 36
3 Mar after 35.3 °C 30 % 40 km/h 0.0 mm Very high 38
4 Mar after 33.9 °C 34 % 32 km/h 0.0 mm High 34
5 Mar after 34.8 °C 29 % 38 km/h 0.0 mm High 37
6 Mar after 35.4 °C 20 % 32 km/h 0.0 mm Very high 38
7 Mar after 36.1 °C 22 % 29 km/h 0.0 mm Very high 39
8 Mar after 35.3 °C 27 % 28 km/h 0.0 mm High 38
9 Mar after 35.3 °C 23 % 22 km/h 0.0 mm High 37

Its twins: fires that started in the same weather

It started with an FWI of 22.1, a minimum humidity of 32% and 1 day without rain. Fires in the area that started in weather like this since 2016: 19.

FWI at the start 22.1
Minimum humidity 32 %
Days without rain 1
this fire chosen twins rest of the area
Almost identicalSimilar

Outlines of the closest twins

Ban Tak fire, March 2023
2,574 ha 10 days FWI 23.1 Min. humidity 33 % 21 km away, in 2023

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

What happened to them

11 days
median duration
2,340 ha
median area
100 %
went past 1,000 ha
3.6 mm
rain at the end (median; 10 of 19 had it)

It burned an area similar to its twins (2,642 ha against a median of 2,340 ha) and lasted 18 days, against 11 days.

In 9 of 19, 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 3.6 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

—first rain
—no rain in ten days
45km/h · max. gust

It was considered over on 27 Feb, and not even 1 mm fell in the following ten days: it went out without rain. Twins with rain when they ended: 10 of 19, with a median of 3.6 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 · 3 Feb 2021
After · 6 Mar 2021

If the day is cloudy, change the date: each satellite passes once a day. In false colour the burnt ground looks brown or red.

Detections table · 79Every 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?
According to the heat detections seen by satellite inside the perimeter, it burned from 10 February 2021 to 27 February 2021 (18 days). The perimeter dates it from 10 February 2021 to 22 February 2021.
How much area did it burn?
The perimeter GWIS (Copernicus) rebuilt from heat detections is 2,642 hectares (26.4 km²). It is an estimate: official national figures may differ.
Which municipalities burned?
The fire only entered Sam Ngao (2,670 ha, 1.0 %).
What was the weather like?
During the fire the temperature reached 34.2 °C, humidity dropped to 23 % and gusts hit 45 km/h. The fire danger index (FWI) reached 36, 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: 19. Their median duration was 11 days and their median area 2,340 ha; 100 % went past 1,000 ha. In 9 of 19, 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 3.6 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 · 1 Changes in area, dates, name, official record or merged pages, compared every night since 24 October 2026.
  1. Last day with fire: 22 February 2021 → 27 February 2021.

RSS Changes to this page With cross-checks and a citable version

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 adjusted with the VIIRS detections inside the perimeter, which said 10 February 2021 to 22 February 2021. 79 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 2020, 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.