Burned area
satellite only16,375ha
Union of 2 GWIS (Copernicus) perimeters: overlapping areas count once.
- Source
- GWIS (Copernicus)
- Date
- 20 Feb 2023 – 6 Apr 2023
+− cross-check
No official record is matched to this page to compare it with.
LA · Laos · –
Sanamxay fire, February 2023 Sanamxay
Out · last detection 6 Apr 2023, 06:24 UTC
The fire started on 20 February 2023 in Sanamxay, Laos, and satellites saw it burning for 46 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 16,375 hectares from heat detections, spread across a single municipality.
This page is probably a fire complex, not a single fire. GWIS merges into one perimeter the fires that touch over weeks, which in large burning seasons can join dozens of separate fires. The total area is reliable; the origin and dates refer to the whole complex.
Other fire pages in the same area and on the same dates:
It is the largest fire in Attapeu since 2016 (of 28 with a page). Number 12 in Laos in 2023, of 239.
Use this data
Compare with…
Use this data
Fire page data · version 2026-11-05matches 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 only46days
20 Feb 2023 to 6 Apr 2023: first and last day with fire on the page.
- Source
- GWIS (Copernicus) · NASA FIRMS · VIIRS
- Date
- last detection: 6 Apr 2023, 06:24 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 only20 Feb 2023
First day with fire seen by the satellites or the perimeter.
- Source
- GWIS (Copernicus) · NASA FIRMS · VIIRS
- Date
- 20 Feb 2023
+− cross-check
No official record is matched to this page, so the alert time and the cause are not known here.
Hotspots
satellite only2,006
VIIRS detections at 375 m. Most intense hotspot: 385 MW.
- Source
- NASA FIRMS · VIIRS (Suomi NPP)
- Date
- 20 Feb 2023 – 6 Apr 2023
+− 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 only2,194MW
Total radiative power on 7 March 2023; hotspots that day: 52.
- Source
- NASA FIRMS · VIIRS (FRP)
- Date
- 7 Mar 2023
+− 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
model25.9FWI · high
Fire Weather Index (Canadian system) computed by WorldFires for the day the fire started. Consecutive days without rain before: 44.
- Source
- WorldFires calculation (Canadian FWI system)
- Date
- 20 Feb 2023, 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
model36.2°C · 40% RH
High of 36.2 °C and minimum humidity of 40% on 22 March 2023; gusts of 32 km/h on 13 March 2023.
- Source
- weather model at the fire’s grid cell
- Date
- 20 Feb 2023 – 6 Apr 2023
- 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≈ 850people
Estimated residents inside the perimeter and 0.18 ha of built-up area (100 m grid, epoch 2025).
- 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
-
logArea: 18,030 → 16,375 ha.
-
· reconstructed GHSLPopulation and built-up area computed
-
· reconstructed weatherWeather and FWI computed from the ERA5 reanalysis
What was saved on 5 November 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
- 16,375 ha
- Dates
- 20 Feb 2023 – 6 Apr 2023
- Name
- Sanamxay
- Official record
- —
Versioned permanent link
https://worldfires.org/en/fire/sanamxay-2023-02?v=2026-11-05A 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 sanamxay-2023-02.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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 2023-02-20 | 24 | 447 | 1 | ||||||||
| 2023-02-21 | 7 | 137 | 1 | ||||||||
| 2023-02-22 | 53 | 715 | 1 | ||||||||
| 2023-02-23 | 26 | 361 | 1 | ||||||||
| 2023-02-24 | 63 | 376 | 1 | ||||||||
| 2023-02-25 | 82 | 621 | 1 | ||||||||
| 2023-02-26 | 70 | 1,020 | 1 | ||||||||
| 2023-02-27 | 76 | 1,850 | 32.1 | 16.7 | 35 | 10.8 | 21.2 | 0 | 25.9 | alto | 1 |
| 2023-02-28 | 58 | 671 | 33.5 | 17.4 | 36 | 9 | 19.4 | 0 | 25.1 | alto | 1 |
| 2023-03-01 | 40 | 556 | 34.4 | 18.3 | 38 | 8.1 | 21.2 | 0 | 24.9 | alto | 1 |
| 2023-03-02 | 46 | 543 | 34 | 20.6 | 32 | 10.5 | 24.1 | 0 | 26.9 | alto | 1 |
| 2023-03-03 | 58 | 621 | 33.5 | 17.8 | 30 | 10.4 | 22 | 0 | 27.3 | alto | 1 |
| 2023-03-04 | 95 | 1,653 | 33.5 | 18.2 | 30 | 10.9 | 23.4 | 0 | 28.1 | alto | 1 |
| 2023-03-05 | 55 | 904 | 32.2 | 17.7 | 32 | 10.1 | 21.2 | 0 | 27.9 | alto | 1 |
| 2023-03-06 | 58 | 811 | 33 | 17.8 | 31 | 7.6 | 20.2 | 0 | 26.6 | alto | 1 |
| 2023-03-07 | 52 | 2,194 | 33.4 | 17.1 | 34 | 7.1 | 22.7 | 0 | 26.6 | alto | 1 |
| 2023-03-08 | 35 | 496 | 34.6 | 19.3 | 35 | 9 | 21.6 | 0 | 28.3 | alto | 1 |
| 2023-03-09 | 46 | 807 | 33.9 | 19.3 | 33 | 8.7 | 18.7 | 0 | 28.4 | alto | 1 |
| 2023-03-10 | 40 | 797 | 34 | 18.8 | 35 | 10.5 | 26.3 | 0 | 30.1 | alto | 1 |
| 2023-03-11 | 44 | 414 | 34.4 | 20.4 | 38 | 9.8 | 23.8 | 0 | 29 | alto | 1 |
| 2023-03-12 | 52 | 581 | 34.7 | 23.1 | 35 | 10 | 20.9 | 0 | 29.5 | alto | 1 |
| 2023-03-13 | 78 | 438 | 33.5 | 20.3 | 30 | 13.3 | 31.7 | 0 | 32.4 | alto | 1 |
| 2023-03-14 | 81 | 957 | 33.1 | 18.3 | 35 | 8.6 | 20.9 | 0 | 29.1 | alto | 1 |
| 2023-03-15 | 57 | 977 | 33.9 | 20.8 | 38 | 9 | 27 | 0 | 28.9 | alto | 1 |
| 2023-03-16 | 40 | 260 | 34 | 21.8 | 39 | 8.6 | 22.7 | 0 | 28.3 | alto | 1 |
| 2023-03-17 | 39 | 429 | 34.6 | 21.1 | 36 | 7.6 | 24.8 | 0 | 27.9 | alto | 1 |
| 2023-03-18 | 31 | 255 | 35.3 | 22.7 | 35 | 7.3 | 22.7 | 0 | 27.9 | alto | 1 |
| 2023-03-19 | 32 | 369 | 34.8 | 24 | 41 | 7.8 | 21.6 | 0 | 27.6 | alto | 1 |
| 2023-03-20 | 31 | 514 | 34 | 22.8 | 43 | 7.9 | 22.7 | 0 | 26.6 | alto | 1 |
| 2023-03-21 | 37 | 534 | 35.5 | 21.7 | 40 | 8.6 | 25.2 | 0.2 | 27.3 | alto | 1 |
| 2023-03-22 | 35 | 236 | 36.2 | 22 | 40 | 9.3 | 26.6 | 0 | 28 | alto | 1 |
| 2023-03-23 | 13 | 87 | 34.9 | 23.8 | 48 | 7.8 | 25.6 | 0.5 | 25.1 | alto | 1 |
| 2023-03-24 | 24 | 179 | 35.7 | 23.4 | 43 | 8.9 | 26.6 | 0.3 | 26 | alto | 1 |
| 2023-03-25 | 66 | 993 | 35.4 | 24 | 44 | 8.1 | 24.8 | 0.3 | 25.7 | alto | 1 |
| 2023-03-26 | 30 | 250 | 35.5 | 23.5 | 42 | 8.6 | 26.6 | 0.4 | 26.2 | alto | 1 |
| 2023-03-27 | 60 | 1,277 | 36.1 | 23.6 | 37 | 8 | 23.8 | 0 | 26.6 | alto | 1 |
| 2023-03-28 | 55 | 707 | 36.2 | 25 | 38 | 9.8 | 22 | 0.1 | 28.1 | alto | 1 |
| 2023-03-29 | 11 | 29 | 33 | 24.8 | 48 | 9.3 | 25.9 | 0.1 | 25.8 | alto | 1 |
| 2023-03-30 | 34 | 279 | 34.9 | 22.3 | 41 | 7.6 | 23.4 | 0 | 24.8 | alto | 1 |
| 2023-03-31 | 18 | 316 | 34.2 | 23.7 | 48 | 7.3 | 22 | 0.6 | 20.7 | moderado | 1 |
| 2023-04-01 | 38 | 438 | 35.2 | 24.2 | 46 | 7.6 | 24.8 | 0.7 | 20.5 | moderado | 1 |
| 2023-04-02 | 28 | 200 | 34 | 23.2 | 51 | 7.4 | 24.5 | 2.5 | 7.9 | bajo | 1 |
| 2023-04-03 | 27 | 289 | 1 | ||||||||
| 2023-04-04 | 21 | 231 | 1 | ||||||||
| 2023-04-05 | 33 | 1,182 | 1 | ||||||||
| 2023-04-06 | 7 | 47 | 1 |
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
- 16,375ha
- GWIS perimeter (Copernicus)
- Duration
- 46days
- 20 Feb 2023 – 6 Apr 2023
- Municipalities hit
- 1
- districts
- Started on
- 20 Feb
- 2023
- Heat detections
- 2,006
- in a single hotspot: 385 MW
- Danger at start
- 26
- High · FWI index
- Average daily power
- 610MW
- detected power per day, on average
Where it burned
HOTSPOTS BY DAY
20 Feb6 Apr
6 Apr 2023
How it evolved, day by day
20 Feb
7 Mar
22 Mar
1 Apr
Fire radiative power detected each day, in megawatts, and number of hotspots. The magenta bar marks the peak day.
The weather it burned in
36°high
32km/h · peak gust
30%lowest humidity
It had gone 44 days without rain (1 mm or more) when it started. Rain came after the fire: 2.5 mm on 2 Apr.
This area had burned before
66% of the perimeter overlaps earlier fires recorded since 2016: 605 ha in 2020, 1,097 ha in 2021, 14,595 ha in 2022. Part of it burned more than once, so the yearly figures add up to more than the 10,838 ha that had burned before.
- 2,159 ha Sanamxay fire, April 2022 6,499 ha in total; the hectares shown are those it shares with this fire
- 2,011 ha Sanamxay fire, April 2022 3,136 ha in total; the hectares shown are those it shares with this fire
- 1,888 ha Sanamxay fire, February 2022 2,075 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).
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).
Berlin boundary: geoBoundaries · Federal Agency for Cartography and Geodesy (dl-de/by-2-0).
This compares size, not location: both shapes are at the same scale, north up, centred on each other.
What happened to each town
-
Sanamxay where it started18,140 ha reached on 20 Feb8.1 %
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 2025Built-up area0.18 ha
Residents≈ 850
Inside the perimeter there were about 0.18 hectares of built-up land and about 850 residents (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) |
|---|---|---|---|---|---|
| 27 Feb | 32.1 °C | 35 % | 21 km/h | 0.0 mm | High 26 |
| 28 Feb | 33.5 °C | 36 % | 19 km/h | 0.0 mm | High 25 |
| 1 Mar | 34.4 °C | 38 % | 21 km/h | 0.0 mm | High 25 |
| 2 Mar | 34.0 °C | 32 % | 24 km/h | 0.0 mm | High 27 |
| 3 Mar | 33.5 °C | 30 % | 22 km/h | 0.0 mm | High 27 |
| 4 Mar | 33.5 °C | 30 % | 23 km/h | 0.0 mm | High 28 |
| 5 Mar | 32.2 °C | 32 % | 21 km/h | 0.0 mm | High 28 |
| 6 Mar | 33.0 °C | 31 % | 20 km/h | 0.0 mm | High 27 |
| 7 Mar | 33.4 °C | 34 % | 23 km/h | 0.0 mm | High 27 |
| 8 Mar | 34.6 °C | 35 % | 22 km/h | 0.0 mm | High 28 |
| 9 Mar | 33.9 °C | 33 % | 19 km/h | 0.0 mm | High 28 |
| 10 Mar | 34.0 °C | 35 % | 26 km/h | 0.0 mm | High 30 |
| 11 Mar | 34.4 °C | 38 % | 24 km/h | 0.0 mm | High 29 |
| 12 Mar | 34.7 °C | 35 % | 21 km/h | 0.0 mm | High 30 |
| 13 Mar | 33.5 °C | 30 % | 32 km/h | 0.0 mm | High 32 |
| 14 Mar | 33.1 °C | 35 % | 21 km/h | 0.0 mm | High 29 |
| 15 Mar | 33.9 °C | 38 % | 27 km/h | 0.0 mm | High 29 |
| 16 Mar | 34.0 °C | 39 % | 23 km/h | 0.0 mm | High 28 |
| 17 Mar | 34.6 °C | 36 % | 25 km/h | 0.0 mm | High 28 |
| 18 Mar | 35.3 °C | 35 % | 23 km/h | 0.0 mm | High 28 |
| 19 Mar | 34.8 °C | 41 % | 22 km/h | 0.0 mm | High 28 |
| 20 Mar | 34.0 °C | 43 % | 23 km/h | 0.0 mm | High 27 |
| 21 Mar | 35.5 °C | 40 % | 25 km/h | 0.2 mm | High 27 |
| 22 Mar | 36.2 °C | 40 % | 27 km/h | 0.0 mm | High 28 |
| 23 Mar | 34.9 °C | 48 % | 26 km/h | 0.5 mm | High 25 |
| 24 Mar | 35.7 °C | 43 % | 27 km/h | 0.3 mm | High 26 |
| 25 Mar | 35.4 °C | 44 % | 25 km/h | 0.3 mm | High 26 |
| 26 Mar | 35.5 °C | 42 % | 27 km/h | 0.4 mm | High 26 |
| 27 Mar | 36.1 °C | 37 % | 24 km/h | 0.0 mm | High 27 |
| 28 Mar | 36.2 °C | 38 % | 22 km/h | 0.1 mm | High 28 |
| 29 Mar | 33.0 °C | 48 % | 26 km/h | 0.1 mm | High 26 |
| 30 Mar | 34.9 °C | 41 % | 23 km/h | 0.0 mm | High 25 |
| 31 Mar | 34.2 °C | 48 % | 22 km/h | 0.6 mm | Moderate 21 |
| 1 Apr | 35.2 °C | 46 % | 25 km/h | 0.7 mm | Moderate 20 |
| 2 Apr | 34.0 °C | 51 % | 24 km/h | 2.5 mm | Low 8 |
Before and after, from space
Drag the line to compare the same ground before the fire and after it.
↔
Before · 13 Feb 2023
After · 13 Apr 2023
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.
The smoke
CAMS · CopernicusOn 19 February 2023 the air beside the fire reached 235 µg/m³ of PM2.5. That day averaged 127: 8.5 times the WHO daily guideline (15).
PM2.5 peak235 µg/m³
Days over the guideline49 days
PM10336 µg/m³
Optical depth2.05
WHO 15
18 Feb1 Mar12 Mar23 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 · 2,006Every 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
- 6,496 haSanamxay15 February 2024 · 44 days · 9 km away
- 4,807 haSanamxay19 February 2020 · 17 days · 12 km away
- 6,499 haSanamxay3 April 2022 · 11 days · 16 km away
- 5,754 haPathoomphoneMarch 2026 · 39 days · 26 km away
- 3,824 haSanamxay19 February 2024 · 32 days · 26 km away
- 3,775 haPaksxongFebruary 2026 · 24 days · 26 km away
Frequently asked questions
- How long did the Sanamxay fire last?
- According to the heat detections seen by satellite inside the perimeter, it burned from 20 February 2023 to 6 April 2023 (46 days). The perimeter dates it from 27 February 2023 to 30 March 2023.
- How much area did it burn?
- The perimeter GWIS (Copernicus) rebuilt from heat detections is 16,375 hectares (163.8 km²). It is an estimate: official national figures may differ.
- Which municipalities burned?
- The fire only entered Sanamxay (18,140 ha, 8.1 %).
- What was the weather like?
- During the fire the temperature reached 36.2 °C, humidity dropped to 30 % and gusts hit 32 km/h. The fire danger index (FWI) reached 32, class High.
- Where does this data come from?
- From the GWIS (Copernicus) burnt perimeter, NASA FIRMS VIIRS hotspots and the administrative boundaries of Laos (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.
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.
- Area: 18,030 → 16,375 ha.
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; 2 polygons grouped in this page.
- Dates adjusted with the VIIRS detections inside the perimeter, which said 27 February 2023 to 30 March 2023. 2,006 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.
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.