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Ngoi fire, March 2023 Ngoi, Pak Xeng

Out · last detection 28 Apr 2023, 06:13 UTC

The fire started on 25 March 2023 in Ngoi, Laos, and satellites saw it burning for 35 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 15,019 hectares from heat detections, spread across 2 municipalities.

It is the 8th largest in Luang Prabang since 2016 (of 295 with a page). Number 14 in Laos in 2023, of 239.

Compare with…

Suggestions: Ngoi · 2019Ngoi · 2020Pak Xeng · 2021Ngoi · 2020

Burnt area
15,019ha
GWIS perimeter (Copernicus)
Duration
35days
25 Mar 2023 – 28 Apr 2023
Municipalities hit
2
districts
Started on
25 Mar
2023
Heat detections
759
in a single hotspot: 400 MW
Danger at start
22
High · FWI index
Average daily power
475MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 25 Mar28 Apr
28 Apr 2023

How it evolved, day by day

25 Mar 2023 · 174 MW · 9 26 Mar 2023 · 92 MW · 4 28 Mar 2023 · 14 MW · 3 29 Mar 2023 · 20 MW · 3 31 Mar 2023 · 152 MW · 6 1 Apr 2023 · 433 MW · 8 2 Apr 2023 · 199 MW · 19 3 Apr 2023 · 85 MW · 10 4 Apr 2023 · 573 MW · 41 5 Apr 2023 · 824 MW · 64 6 Apr 2023 · 1,245 MW · 65 7 Apr 2023 · 445 MW · 21 8 Apr 2023 · 1,304 MW · 27 9 Apr 2023 · 7 MW · 1 10 Apr 2023 · 3 MW · 1 11 Apr 2023 · 2,825 MW · 54 12 Apr 2023 · 87 MW · 23 13 Apr 2023 · 701 MW · 36 14 Apr 2023 · 1,565 MW · 59 15 Apr 2023 · 925 MW · 34 16 Apr 2023 · 1,141 MW · 34 17 Apr 2023 · 57 MW · 16 18 Apr 2023 · 328 MW · 28 19 Apr 2023 · 594 MW · 61 20 Apr 2023 · 461 MW · 30 21 Apr 2023 · 88 MW · 20 22 Apr 2023 · 262 MW · 51 23 Apr 2023 · 47 MW · 11 24 Apr 2023 · 40 MW · 11 25 Apr 2023 · 23 MW · 8 28 Apr 2023 · 3 MW · 1
25 Mar 1 Apr 6 Apr 11 Apr 16 Apr 21 Apr 28 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

38°high
43km/h · peak gust
24%lowest humidity

It had gone one day without rain (1 mm or more) when it started. Rain came after the fire: 1.2 mm on 25 Apr.

This area had burned before

77% of the perimeter overlaps earlier fires recorded since 2016: 974 ha in 2016, 451 ha in 2018, 6,542 ha in 2019, 4,949 ha in 2020, 2,495 ha in 2021, 900 ha in 2022. Part of it burned more than once, so the yearly figures add up to more than the 11,514 ha that had burned before.

How big is it?

10 km
It burned the equivalent of 9.5% of the area of London (150 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. Ngoi where it started
    10,415 ha reached on 25 Mar
    5.4 %
  2. Pak Xeng
    4,666 ha reached on 25 Mar
    2.8 %

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.

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)
1 Apr 33.1 °C 35 % 37 km/h 0.0 mm High 22
2 Apr 33.9 °C 31 % 43 km/h 0.0 mm High 28
3 Apr 33.7 °C 29 % 42 km/h 0.0 mm High 29
4 Apr 34.1 °C 27 % 41 km/h 0.0 mm High 31
5 Apr 34.2 °C 26 % 33 km/h 0.0 mm High 29
6 Apr 34.7 °C 27 % 21 km/h 0.0 mm High 26
7 Apr 33.7 °C 35 % 28 km/h 0.0 mm High 29
8 Apr 30.0 °C 52 % 31 km/h 0.6 mm Moderate 20
9 Apr 31.9 °C 50 % 36 km/h 0.9 mm Moderate 15
10 Apr 34.6 °C 35 % 34 km/h 0.0 mm High 25
11 Apr 35.9 °C 32 % 30 km/h 0.0 mm High 26
12 Apr 35.4 °C 33 % 28 km/h 0.0 mm High 27
13 Apr 35.2 °C 36 % 32 km/h 0.0 mm High 29
14 Apr 36.3 °C 35 % 31 km/h 0.0 mm High 28
15 Apr 36.0 °C 32 % 29 km/h 0.0 mm High 30
16 Apr 33.8 °C 43 % 34 km/h 0.0 mm High 26
17 Apr 34.4 °C 40 % 41 km/h 0.0 mm High 30
18 Apr 37.5 °C 28 % 38 km/h 0.0 mm High 35
19 Apr 37.7 °C 24 % 37 km/h 0.0 mm High 38
20 Apr 37.0 °C 29 % 36 km/h 0.0 mm High 38
21 Apr 36.5 °C 31 % 36 km/h 0.0 mm High 38
22 Apr 35.0 °C 36 % 35 km/h 0.8 mm High 28
23 Apr 37.1 °C 25 % 31 km/h 0.0 mm High 34
24 Apr 34.5 °C 34 % 36 km/h 0.0 mm High 32
25 Apr 35.3 °C 35 % 26 km/h 1.2 mm High 23

Before and after, from space

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

Before · 18 Mar 2023
After · 5 May 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 7 April 2023 the air beside the fire reached 1,915 µg/m³ of PM2.5. That day averaged 1,074: 72 times the WHO daily guideline (15).

PM2.5 peak1,915 µg/m³
Days over the guideline37 days
PM102,734 µg/m³
Optical depth12.16
23242526272829303112345678910111213141516171819202122232425262728
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 · 759Every 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 Ngoi fire last?
According to the heat detections seen by satellite inside the perimeter, it burned from 25 March 2023 to 28 April 2023 (35 days). The perimeter dates it from 1 April 2023 to 23 April 2023.
How much area did it burn?
The perimeter GWIS (Copernicus) rebuilt from heat detections is 15,019 hectares (150.2 km²). It is an estimate: official national figures may differ.
Which municipalities burned?
The fire entered 2 municipalities: Ngoi (10,415 ha, 5.4 %); Pak Xeng (4,666 ha, 2.8 %).
What was the weather like?
During the fire the temperature reached 37.7 °C, humidity dropped to 24 % and gusts hit 43 km/h. The fire danger index (FWI) reached 38, class Very 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; 3 polygons grouped in this page.
  • Dates adjusted with the VIIRS detections inside the perimeter, which said 1 April 2023 to 23 April 2023. 759 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.

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.