Nalae fire, April 2023 Nalae, Xay
The fire started on 6 April 2023 in Nalae, Laos, and satellites saw it burning for 11 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 3,443 hectares from heat detections, spread across 2 municipalities.
It is the 10th largest in Luang Namtha since 2016 (of 40 with a page). Number 81 in Laos in 2023, of 239.
Compare with…
Suggestions: Nalae · 2018Nalae · 2020Namor · 2017Namor · 2019
- Burnt area
- 3,443ha
- GWIS perimeter (Copernicus)
- Duration
- 11days
- 6 Apr 2023 – 16 Apr 2023
- Municipalities hit
- 2
- districts
- Started on
- 6 Apr
- 2023
- Heat detections
- 120
- in a single hotspot: 0 MW
- Average daily power
- 487MW
- detected power per day, on average
Where it burned
How it evolved, day by day
Fire radiative power detected each day, in megawatts, and number of hotspots. The magenta bar marks the peak day.
This area had burned before
42% of the perimeter overlaps earlier fires recorded since 2016: 639 ha in 2016, 607 ha in 2017, 52 ha in 2018, 75 ha in 2020, 436 ha in 2021. Part of it burned more than once, so the yearly figures add up to more than the 1,429 ha that had burned before.
- 52 ha Nalae fire, April 2018 3,231 ha in total; the hectares shown are those it shares with this fire
- 40 ha Nalae fire, March 2020 2,098 ha in total; the hectares shown are those it shares with this fire
- 27 ha Namor fire, April 2017 29,869 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
-
Nalae where it started2,792 ha1.6 %
-
669 ha0.3 %
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 2025Inside the perimeter there were about 1.7 hectares of built-up land and about 950 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
Before and after, from space
Drag the line to compare the same ground before the fire and after it.
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 8 April 2023 the air beside the fire reached 969 µg/m³ of PM2.5. That day averaged 628: 42 times the WHO daily guideline (15).
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 · 0Every satellite heat detection, one by one, with time, satellite, power and coordinates.
| Date and time | Satellite | FRP (MW) | Lat | Lon |
|---|
Other fires nearby
Frequently asked questions
- How long did the Nalae fire last?
- GWIS (Copernicus) dates it between 6 April 2023 and 16 April 2023: 11 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 3,443 hectares (34.4 km²). It is an estimate: official national figures may differ.
- Which municipalities burned?
- The fire entered 2 municipalities: Nalae (2,792 ha, 1.6 %); Xay (669 ha, 0.3 %).
- 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.
- Last day with fire: 22 April 2023 → 16 April 2023.
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 from the perimeter: the VIIRS detections inside it did not change them. No Suomi-NPP VIIRS detections on those dates.
- We have not matched this page with any official record.
- 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.