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Nan fire, 23 March 2023 Nan, Luangprabang, Xieng Ngeun

Out · last detection 12 Apr 2023, 18:43 UTC

The fire started on 23 March 2023 in Nan, Laos, and satellites saw it burning for 21 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 2,603 hectares from heat detections, spread across 3 municipalities.

It is the 171th largest in Luang Prabang since 2016 (of 295 with a page). Number 140 in Laos in 2023, of 239.

Compare with…

Suggestions: Nan · 2020Nan · 2019Nan · 2018Xieng Ngeun · 2018

Burnt area
2,603ha
GWIS perimeter (Copernicus)
Duration
21days
23 Mar 2023 – 12 Apr 2023
Municipalities hit
3
districts
Started on
23 Mar
2023
Heat detections
108
in a single hotspot: 222 MW
Danger at start
34
High · FWI index
Average daily power
218MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 23 Mar12 Apr
12 Apr 2023

How it evolved, day by day

23 Mar 2023 · 12 MW · 4 24 Mar 2023 · 2 MW · 1 25 Mar 2023 · 97 MW · 2 26 Mar 2023 · 1 MW · 1 30 Mar 2023 · 8 MW · 2 31 Mar 2023 · 52 MW · 3 1 Apr 2023 · 121 MW · 6 2 Apr 2023 · 1,191 MW · 15 3 Apr 2023 · 587 MW · 18 4 Apr 2023 · 231 MW · 26 5 Apr 2023 · 929 MW · 18 6 Apr 2023 · 2 MW · 1 10 Apr 2023 · 13 MW · 1 11 Apr 2023 · 4 MW · 1 12 Apr 2023 · 19 MW · 9
23 Mar 26 Mar 1 Apr 2 Apr 4 Apr 10 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

37°high
48km/h · peak gust
24%lowest humidity

It had gone 3 days without rain (1 mm or more) when it started. Rain came after the fire: 2.1 mm on 22 Apr.

This area had burned before

91% of the perimeter overlaps earlier fires recorded since 2016: 368 ha in 2016, 657 ha in 2017, 1,093 ha in 2018, 1,476 ha in 2019, 2,569 ha in 2020. Part of it burned more than once, so the yearly figures add up to more than the 2,364 ha that had burned before.

How big is it?

10 km
It burned the equivalent of 1.6% 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. Nan where it started
    1,970 ha
    1.4 %
  2. Luangprabang
    585 ha
    0.7 %
  3. Xieng Ngeun
    65 ha
    0.0 %

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 2025
Built-up area< 0.1 ha
Residents≈ 400

Inside the perimeter there were about 0.02 hectares of built-up land and about 400 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)
23 Mar 35.8 °C 24 % 48 km/h 0.1 mm High 34
24 Mar 34.8 °C 28 % 38 km/h 0.0 mm High 31
25 Mar 35.2 °C 27 % 42 km/h 0.0 mm High 32
26 Mar 33.8 °C 29 % 43 km/h 0.0 mm High 33
27 Mar 33.2 °C 35 % 38 km/h 0.0 mm High 30
28 Mar 32.7 °C 44 % 42 km/h 0.1 mm High 26
29 Mar 32.8 °C 43 % 42 km/h 0.2 mm High 26
30 Mar 31.0 °C 49 % 32 km/h 0.5 mm High 22
31 Mar 32.8 °C 39 % 38 km/h 0.0 mm High 23
1 Apr 34.2 °C 34 % 42 km/h 0.1 mm High 27
2 Apr 35.6 °C 25 % 47 km/h 0.0 mm High 35
3 Apr 34.7 °C 28 % 45 km/h 0.0 mm High 34
4 Apr 35.3 °C 26 % 42 km/h 0.0 mm High 35
5 Apr 34.9 °C 26 % 34 km/h 0.0 mm High 33
6 Apr 35.6 °C 26 % 24 km/h 0.0 mm High 30
7 Apr 34.2 °C 34 % 37 km/h 0.0 mm High 33
8 Apr 32.6 °C 47 % 31 km/h 0.2 mm High 26
9 Apr 33.6 °C 45 % 40 km/h 0.2 mm High 28
10 Apr 35.5 °C 36 % 40 km/h 0.0 mm High 29
11 Apr 37.4 °C 30 % 33 km/h 0.0 mm High 31
12 Apr 36.7 °C 31 % 32 km/h 0.0 mm High 32
13 Apr after 36.0 °C 36 % 39 km/h 0.0 mm High 33
14 Apr after 37.7 °C 32 % 35 km/h 0.0 mm High 32
15 Apr after 37.1 °C 29 % 27 km/h 0.1 mm High 31
16 Apr after 34.1 °C 45 % 40 km/h 0.4 mm High 30
17 Apr after 34.9 °C 43 % 41 km/h 0.0 mm High 30
18 Apr after 38.3 °C 29 % 40 km/h 0.0 mm High 36
19 Apr after 38.5 °C 25 % 37 km/h 0.0 mm Very high 38
20 Apr after 37.0 °C 33 % 38 km/h 0.0 mm High 37
21 Apr after 35.7 °C 37 % 38 km/h 0.3 mm High 34
22 Apr after 35.0 °C 38 % 36 km/h 2.1 mm Moderate 17

Before and after, from space

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

Before · 16 Mar 2023
After · 19 Apr 2023

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 27 March 2023 the air beside the fire reached 435 µg/m³ of PM2.5. That day averaged 181: 12 times the WHO daily guideline (15).

PM2.5 peak435 µg/m³
Days over the guideline26 days
PM10622 µg/m³
Optical depth2.84
2122232425262728293031123456789101112131415
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 · 108Every 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 Laos ›

Frequently asked questions

How long did the Nan fire last?
According to the heat detections seen by satellite inside the perimeter, it burned from 23 March 2023 to 12 April 2023 (21 days). The perimeter dates it from 30 March 2023 to 5 April 2023.
How much area did it burn?
The perimeter GWIS (Copernicus) rebuilt from heat detections is 2,603 hectares (26.0 km²). It is an estimate: official national figures may differ.
Which municipalities burned?
The fire entered 3 municipalities: Nan (1,970 ha, 1.4 %); Luangprabang (585 ha, 0.7 %); Xieng Ngeun (65 ha, 0.0 %).
What was the weather like?
During the fire the temperature reached 37.4 °C, humidity dropped to 24 % and gusts hit 48 km/h. The fire danger index (FWI) reached 35, 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 Changes in area, dates, name, official record or merged pages, compared every night since 24 October 2026.

No changes since 24 October 2026.

RSS Changes to this page

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.

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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 30 March 2023 to 5 April 2023. 108 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.