Burned area
satellite only1,377ha
Perimeter published by GWIS (Copernicus).
- Source
- GWIS (Copernicus)
- Date
- 5 Mar 2021 – 11 Mar 2021
+− cross-check
No official record is matched to this page to compare it with.
TH · Thailand · –
Sam Ngao fire, 5 March 2021 สามเงา · Sam Ngao
Out · last detection 11 Mar 2021, 05:58 UTC
The fire started on 5 March 2021 in Sam Ngao, Thailand, and satellites saw it burning for 7 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 1,377 hectares from heat detections, spread across a single municipality.
It is the 164th largest in Tak Province since 2016 (of 266 with a page). Number 94 in Thailand in 2021, of 187.
The power measured by the satellite is low (15.5 MW in the strongest hotspot), more typical of grass or stubble burning, or a slow surface fire, than of a large crown fire.
Use this data
Compare with…
Use this data
Fire page data · version 2026-10-26matches the official recordwith caveatssatellite onlymodel
When copying, the sentence is
Tick the figures you want: they make up the lede and the CSV.
Duration by satellite
satellite only7days
5 Mar 2021 to 11 Mar 2021: first and last day with fire on the page.
- Source
- GWIS (Copernicus) · NASA FIRMS · VIIRS
- Date
- last detection: 11 Mar 2021, 05:58 UTC
+− cross-check
Satellites pass a few times a day and cloud or smoke can hide the fire: a lack of detections is not an official extinction. Each country’s emergency service declares a fire contained or out.
Start
satellite only5 Mar 2021
First day with fire seen by the satellites or the perimeter.
- Source
- GWIS (Copernicus) · NASA FIRMS · VIIRS
- Date
- 5 Mar 2021
+− cross-check
No official record is matched to this page, so the alert time and the cause are not known here.
Hotspots
satellite only39
VIIRS detections at 375 m. Most intense hotspot: 15 MW.
- Source
- NASA FIRMS · VIIRS (Suomi NPP)
- Date
- 5 Mar 2021 – 11 Mar 2021
+− cross-check
There is no official record to compare with. Each hotspot is a pixel detected in one satellite pass, not a separate fire.
The worst day
satellite only38MW
Total radiative power on 8 March 2021; hotspots that day: 8.
- Source
- NASA FIRMS · VIIRS (FRP)
- Date
- 8 Mar 2021
+− cross-check
Fire radiative power (FRP) measures the energy the fire gives off when the satellite passes. Added up by day, it compares intensity, not area.
Danger at the start
model44.3FWI · very high
Fire Weather Index (Canadian system) computed by WorldFires for the day the fire started. Consecutive days without rain before: 60.
- Source
- WorldFires calculation (Canadian FWI system)
- Date
- 5 Mar 2021, local noon
- Model
- ERA5 0,25° (ECMWF · Copernicus C3S) · Open-Meteo.com
+− cross-check
This is an index computed from weather model data, not a measurement of the fire nor an official warning. Danger warnings are issued by each country’s authority. Emergency number and official warnings
Weather during the fire
model40.6°C · 16% RH
High of 40.6 °C and minimum humidity of 16% on 7 March 2021; gusts of 38 km/h on 5 March 2021.
- Source
- weather model at the fire’s grid cell
- Date
- 5 Mar 2021 – 11 Mar 2021
- Model
- ERA5 0,25° (ECMWF · Copernicus C3S) · Open-Meteo.com
+− cross-check
These are model values for a cell of about 25 km, not from a weather station: they may differ from what was measured on the ground.
Living inside
model≈ 70people
Estimated residents inside the perimeter and 0.69 ha of built-up area (100 m grid, epoch 2020).
- Source
- GHSL R2023A · JRC
- Date
- calculated on 24 October 2026
+− cross-check
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.
This page’s change log has been kept since 24 October 2026: every night what it publishes is compared and the difference is logged. Anything earlier is reconstructed from each source’s date and marked as reconstructed.
Show
-
· reconstructed weatherWeather and FWI computed from the ERA5 reanalysis
-
logLast day with fire: 10 March 2021 → 11 March 2021.
-
logStart date: 7 March 2021 → 5 March 2021.
-
· reconstructed GHSLPopulation and built-up area computed
What was saved on 26 October 2026
Every night a snapshot of what the page shows is saved. If anything changes, it appears in the list as a log entry.
- Area
- 1,377 ha
- Dates
- 5 Mar 2021 – 11 Mar 2021
- Name
- Sam Ngao
- Official record
- —
Versioned permanent link
https://worldfires.org/en/fire/sam-ngao-2021-03-3?v=2026-10-26A version keeps the area, dates, name and official record; the area as it was logged (changes under 2% are not logged). The map, hotspots and weather always show today’s data.
Citation
A lede of about 60 words figures only, no adjectives
CSV for this fire sam-ngao-2021-03-3.csv · daily, no individual hotspots
| fecha | focos_viirs | frp_mw | tmax_c | tmin_c | hr_min_pct | viento_max_kmh | racha_max_kmh | precip_mm | fwi | clase_fwi | dentro_del_incendio |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 2021-03-05 | 0 | 0 | 39 | 22.1 | 24 | 12.9 | 37.8 | 0 | 44.3 | muy_alto | 1 |
| 2021-03-06 | 0 | 0 | 39.8 | 20.1 | 16 | 8.4 | 29.5 | 0 | 44.5 | muy_alto | 1 |
| 2021-03-07 | 8 | 21 | 40.6 | 19.8 | 16 | 7.3 | 22.7 | 0 | 42.9 | muy_alto | 1 |
| 2021-03-08 | 8 | 38 | 39.3 | 21.3 | 22 | 9.2 | 20.9 | 0 | 46.6 | muy_alto | 1 |
| 2021-03-09 | 13 | 29 | 39.3 | 22 | 18 | 9.4 | 20.5 | 0 | 41.3 | muy_alto | 1 |
| 2021-03-10 | 9 | 13 | 39.1 | 22.6 | 23 | 9.2 | 29.2 | 0 | 46.3 | muy_alto | 1 |
| 2021-03-11 | 1 | 4 | 37.9 | 23.2 | 28 | 8.5 | 25.2 | 0 | 43.2 | muy_alto | 1 |
| 2021-03-12 | 0 | 0 | 37.8 | 24.2 | 31 | 7.9 | 23.4 | 0 | 38.2 | muy_alto | 0 |
| 2021-03-13 | 0 | 0 | 37.5 | 24.2 | 32 | 6.7 | 23.4 | 0 | 38.8 | muy_alto | 0 |
| 2021-03-14 | 0 | 0 | 36.2 | 24.9 | 37 | 6.5 | 23.8 | 0 | 38.5 | muy_alto | 0 |
| 2021-03-15 | 0 | 0 | 38.7 | 24.3 | 28 | 7.6 | 24.8 | 0 | 37.3 | alto | 0 |
| 2021-03-16 | 0 | 0 | 39.9 | 23.4 | 26 | 7.2 | 22.3 | 0 | 35.6 | alto | 0 |
| 2021-03-17 | 0 | 0 | 39.4 | 24.1 | 28 | 7.3 | 23 | 0 | 37.8 | alto | 0 |
| 2021-03-18 | 0 | 0 | 39.8 | 24.9 | 28 | 7.6 | 22.3 | 0 | 35.2 | alto | 0 |
| 2021-03-19 | 0 | 0 | 41.2 | 24.7 | 27 | 7.4 | 27.4 | 0.1 | 42.3 | muy_alto | 0 |
| 2021-03-20 | 0 | 0 | 42.1 | 25.1 | 23 | 7.9 | 32.8 | 0.4 | 42.9 | muy_alto | 0 |
| 2021-03-21 | 0 | 0 | 41.7 | 24.8 | 23 | 8.9 | 36 | 0.2 | 41.3 | muy_alto | 0 |
It is generated in your browser from this page’s data: one file per fire, aggregated by day and without individual hotspots.
Live widget for your story
It updates itself while the fire is still active and links to this page. Free, with the attribution shown at the bottom.
Sources for this page: GWIS (Copernicus), NASA FIRMS (VIIRS), ERA5 (ECMWF/Copernicus C3S) · Open-Meteo.com (CC BY 4.0), GHSL (JRC). Open-Meteo.com · How we build fire pages: methodology
- Burnt area
- 1,377ha
- GWIS perimeter (Copernicus)
- Duration
- 7days
- 5 Mar 2021 – 11 Mar 2021
- Municipalities hit
- 1
- districts
- Started on
- 5 Mar
- 2021
- Heat detections
- 39
- in a single hotspot: 15 MW
- Danger at start
- 44
- Very high · FWI index
- Average daily power
- 21MW
- detected power per day, on average
Where it burned
HOTSPOTS BY DAY
5 Mar11 Mar
11 Mar 2021
How it evolved, day by day
7 Mar
8 Mar
9 Mar
10 Mar
11 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
41°high
38km/h · peak gust
16%lowest humidity
It had gone more than two months without rain (1 mm or more) when it started.
This area had burned before
89% of the perimeter overlaps earlier fires recorded since 2016: 797 ha in 2017, 144 ha in 2018, 927 ha in 2019, 264 ha in 2020. Part of it burned more than once, so the yearly figures add up to more than the 1,224 ha that had burned before.
- 625 ha Ban Tak fire, March 2017 7,881 ha in total; the hectares shown are those it shares with this fire
- 264 ha Sam Ngao fire, March 2019 6,284 ha in total; the hectares shown are those it shares with this fire
- 7 ha Sam Ngao fire, January 2020 1,316 ha in total; the hectares shown are those it shares with this fire
How big is it?
London boundary: geoBoundaries · Office for National Statistics (Open Government Licence v3.0).
Bangkok boundary: geoBoundaries · OpenStreetMap, Wambacher · © OpenStreetMap contributors (ODbL 1.0).
Paris boundary: geoBoundaries · Institut national de l'information géographique et forestière (IGN-F) (Etalab Open License 2.0).
Madrid boundary: geoBoundaries · Open Data ESRI, IGN Central Registry of Cartography Area (CC BY 4.0).
This compares size, not location: both shapes are at the same scale, north up, centred on each other.
What happened to each town
-
1,382 ha reached on 7 Mar0.5 %
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 2020Built-up area0.69 ha
Residents≈ 70
Inside the perimeter there were about 0.69 hectares of built-up land and about 70 residents (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)
Started with 60 days without rain: 15 % of the area in Thailand
| Day | High | Min. humidity | Peak gust | Rain | Danger (FWI) |
|---|---|---|---|---|---|
| 5 Mar | 39.0 °C | 24 % | 38 km/h | 0.0 mm | Very high 44 |
| 6 Mar | 39.8 °C | 16 % | 30 km/h | 0.0 mm | Very high 44 |
| 7 Mar | 40.6 °C | 16 % | 23 km/h | 0.0 mm | Very high 43 |
| 8 Mar | 39.3 °C | 22 % | 21 km/h | 0.0 mm | Very high 47 |
| 9 Mar | 39.3 °C | 18 % | 20 km/h | 0.0 mm | Very high 41 |
| 10 Mar | 39.1 °C | 23 % | 29 km/h | 0.0 mm | Very high 46 |
| 11 Mar | 37.9 °C | 28 % | 25 km/h | 0.0 mm | Very high 43 |
| 12 Mar after | 37.8 °C | 31 % | 23 km/h | 0.0 mm | Very high 38 |
| 13 Mar after | 37.5 °C | 32 % | 23 km/h | 0.0 mm | Very high 39 |
| 14 Mar after | 36.2 °C | 37 % | 24 km/h | 0.0 mm | Very high 38 |
| 15 Mar after | 38.7 °C | 28 % | 25 km/h | 0.0 mm | High 37 |
| 16 Mar after | 39.9 °C | 26 % | 22 km/h | 0.0 mm | High 36 |
| 17 Mar after | 39.4 °C | 28 % | 23 km/h | 0.0 mm | High 38 |
| 18 Mar after | 39.8 °C | 28 % | 22 km/h | 0.0 mm | High 35 |
| 19 Mar after | 41.2 °C | 27 % | 27 km/h | 0.1 mm | Very high 42 |
| 20 Mar after | 42.1 °C | 23 % | 33 km/h | 0.4 mm | Very high 43 |
| 21 Mar after | 41.7 °C | 23 % | 36 km/h | 0.2 mm | Very high 41 |
Its twins: fires that started in the same weather
It started with an FWI of 44.3, a minimum humidity of 24% and more than two months without rain. Fires in the area that started in weather like this since 2016: 32.
FWI at the start
44.3
Minimum humidity
24 %
Days without rain
60+
this fire
chosen twins
rest of the area
Almost identicalSimilar
Outlines of the closest twins
This fire · Sam Ngao fire, 5 March 2021
1,377 ha
7 days
FWI 44.3
Min. humidity 24 %
Si Satchanalai fire, March 2020
1,089 ha
8 days
FWI 44.6
Min. humidity 23 %
85 km away, in 2020
First rain (1 mm or more) after it ended: none in the following ten days.
Thoen fire, March 2020
3,409 ha
15 days
FWI 43.3
Min. humidity 23 %
68 km away, in 2020
First rain (1 mm or more) after it ended: 7.1 mm on 13 Apr.
Mueang Pan fire, March 2020
1,181 ha
6 days
FWI 43.3
Min. humidity 24 %
166 km away, in 2020
First rain (1 mm or more) after it ended: none in the following ten days.
Si Satchanalai fire, March 2020
2,864 ha
12 days
FWI 44.5
Min. humidity 22 %
93 km away, in 2020
First rain (1 mm or more) after it ended: 5.6 mm on 13 Apr.
Si Satchanalai fire, March 2020
1,115 ha
3 days
FWI 47.5
Min. humidity 24 %
109 km away, in 2020
First rain (1 mm or more) after it ended: none in the following ten days.
What happened to them
- 9 days
- median duration
- 1,420 ha
- median area
- 100 %
- went past 1,000 ha
- 4.0 mm
- rain at the end (median; 21 of 32 had it)
It burned an area similar to its twins (1,377 ha against a median of 1,420 ha) and lasted 7 days, against 9 days.
In 11 of 32, 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 4.0 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
38km/h · max. gust
It was considered over on 11 Mar, and not even 1 mm fell in the following ten days: it went out without rain. Twins with rain when they ended: 21 of 32, with a median of 4.0 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.
Before and after, from space
Drag the line to compare the same ground before the fire and after it.
↔
Before · 26 Feb 2021
After · 18 Mar 2021
Sentinel-2 did not pass over on that day. Try another date, or use false colour, which is daily.
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 · 39Every 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 time | Satellite | FRP (MW) | Lat | Lon |
|---|
Other fires nearby
- 18,150 haBan Tak บ้านตาก2 April 2026 · 23 days · 12 km away
- 11,703 haSam Ngao สามเงา18 March 2023 · 19 days · 14 km away
- 18,226 haMae Phrik แม่พริก6 March 2025 · 27 days · 24 km away
- 19,078 haMae Ramat แม่ระมาด18 March 2026 · 20 days · 28 km away
- 10,328 haSam Ngao สามเงา16 March 2025 · 16 days · 30 km away
- 21,073 haMae Phrik แม่พริกFebruary 2019 · 37 days · 31 km away
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 5 March 2021 to 11 March 2021 (7 days). The perimeter dates it from 7 March 2021 to 10 March 2021.
- How much area did it burn?
- The perimeter GWIS (Copernicus) rebuilt from heat detections is 1,377 hectares (13.8 km²). It is an estimate: official national figures may differ.
- Which municipalities burned?
- The fire only entered Sam Ngao (1,382 ha, 0.5 %).
- What was the weather like?
- During the fire the temperature reached 40.6 °C, humidity dropped to 16 % and gusts hit 38 km/h. The fire danger index (FWI) reached 47, 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.
- 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: 32. Their median duration was 9 days and their median area 1,420 ha; 100 % went past 1,000 ha. In 11 of 32, 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 4.0 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 · 2 Changes in area, dates, name, official record or merged pages, compared every night since 24 October 2026.
- Last day with fire: 10 March 2021 → 11 March 2021.
- Start date: 7 March 2021 → 5 March 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
How we know this
- Perimeter: GWIS (Copernicus), rebuilt from heat detections rather than mapped on imagery.
- Dates adjusted with the VIIRS detections inside the perimeter, which said 7 March 2021 to 10 March 2021. 39 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.
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.