How long did the Xay fire last?

According to the heat detections seen by satellite inside the perimeter, it burned from 24 March 2024 to 14 April 2024 (22 days). The perimeter dates it from 28 March 2024 to 7 April 2024.

How much area did it burn?

The perimeter GWIS (Copernicus) rebuilt from heat detections is 7,906 hectares (79.1 km²). It is an estimate: official national figures may differ.

Which municipalities burned?

The fire entered 3 municipalities: Nga (4,052 ha, 2.1 %); Xay (2,642 ha, 1.2 %); Nambak (1,255 ha, 0.6 %).

What was the weather like?

During the fire the temperature reached 35.0 °C, humidity dropped to 24 % and gusts hit 45 km/h. The fire danger index (FWI) reached 28, 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.

LA · Laos · 2024-03-24 → 2024-04-14

Xay fire, 24 March 2024 Nga, Xay, Nambak

Out · last detection 14 Apr 2024, 06:12 UTC

The fire started on 24 March 2024 in Xay, Laos, and satellites saw it burning for 22 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 7,906 hectares from heat detections, spread across 3 municipalities.

It is the 24th largest in Oudomxay since 2016 (of 239 with a page). Number 3 in Laos in 2024, of 113.

Compare with…

Suggestions: Nga · 2020 Nga · 2017 Nga · 2016 Nga · 2018

Burnt area: 7,906ha; GWIS perimeter (Copernicus)
Duration: 22days; 24 Mar 2024 – 14 Apr 2024
Municipalities hit: 3; districts
Started on: 24 Mar; 2024
Heat detections: 368; in a single hotspot: 218 MW
Danger at start: 18; Moderate · FWI index
Average daily power: 580MW; detected power per day, on average

HOTSPOTS BY DAY 24 Mar14 Apr

Play back 14 Apr 2024

How it evolved, day by day

24 Mar 27 Mar 30 Mar 2 Apr 4 Apr 5 Apr 8 Apr 14 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

35°high

45km/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: 2.1 mm on 15 Apr.

This area had burned before

62% of the perimeter overlaps earlier fires recorded since 2016: 528 ha in 2016, 1,561 ha in 2017, 1,368 ha in 2018, 37 ha in 2019, 3,527 ha in 2020, 906 ha in 2022, 315 ha in 2023. Part of it burned more than once, so the yearly figures add up to more than the 4,909 ha that had burned before.

How big is it?

It burned the equivalent of 5% of the area of London (79 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

Nga

4,052 ha

2.1 %
Xay where it started

2,642 ha

1.2 %
Nambak

1,255 ha

0.6 %

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 area0.32 ha

Residents≈ 1,000

Inside the perimeter there were about 0.32 hectares of built-up land and about 1,000 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)
24 Mar	31.6 °C	29 %	38 km/h	0.0 mm	Moderate 18
25 Mar	32.5 °C	27 %	24 km/h	0.0 mm	Moderate 18
26 Mar	31.8 °C	33 %	26 km/h	0.0 mm	Moderate 18
27 Mar	30.4 °C	46 %	45 km/h	0.5 mm	Moderate 18
28 Mar	30.4 °C	43 %	35 km/h	0.3 mm	Moderate 16
29 Mar	30.2 °C	42 %	41 km/h	3.7 mm	Very low 3
30 Mar	31.6 °C	34 %	43 km/h	0.0 mm	Moderate 15
31 Mar	33.0 °C	32 %	44 km/h	0.0 mm	Moderate 19
1 Apr	34.1 °C	24 %	45 km/h	0.0 mm	High 25
2 Apr	33.8 °C	26 %	45 km/h	0.0 mm	High 26
3 Apr	34.6 °C	29 %	40 km/h	0.0 mm	High 26
4 Apr	35.0 °C	29 %	35 km/h	0.0 mm	High 26
5 Apr	34.2 °C	33 %	34 km/h	0.0 mm	High 27
6 Apr	34.9 °C	34 %	36 km/h	0.0 mm	High 28
7 Apr	34.9 °C	36 %	34 km/h	0.0 mm	High 27
8 Apr	34.4 °C	42 %	28 km/h	0.0 mm	High 23
9 Apr	32.5 °C	48 %	31 km/h	8.2 mm	Very low 3
10 Apr	28.7 °C	63 %	27 km/h	1.7 mm	Very low 3
11 Apr	31.4 °C	50 %	25 km/h	0.5 mm	Low 9
12 Apr	32.5 °C	45 %	31 km/h	0.9 mm	Low 10
13 Apr	34.3 °C	36 %	34 km/h	0.1 mm	Moderate 19
14 Apr	34.0 °C	37 %	33 km/h	0.1 mm	Moderate 20
15 Apr after	31.8 °C	42 %	36 km/h	2.1 mm	Low 10

Before and after, from space

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

↔

Before · 17 Mar 2024

After · 21 Apr 2024

Before After

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 9 April 2024 the air beside the fire reached 150 µg/m³ of PM2.5. That day averaged 102: 6.8 times the WHO daily guideline (15).

PM2.5 peak150 µg/m³

Days over the guideline25 days

PM10215 µg/m³

Optical depth2.99

WHO 15

222324252627282930311234567891011121314151617

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 · 368Every 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

All fires in Laos ›

Frequently asked questions

How long did the Xay fire last?: According to the heat detections seen by satellite inside the perimeter, it burned from 24 March 2024 to 14 April 2024 (22 days). The perimeter dates it from 28 March 2024 to 7 April 2024.
How much area did it burn?: The perimeter GWIS (Copernicus) rebuilt from heat detections is 7,906 hectares (79.1 km²). It is an estimate: official national figures may differ.
Which municipalities burned?: The fire entered 3 municipalities: Nga (4,052 ha, 2.1 %); Xay (2,642 ha, 1.2 %); Nambak (1,255 ha, 0.6 %).
What was the weather like?: During the fire the temperature reached 35.0 °C, humidity dropped to 24 % and gusts hit 45 km/h. The fire danger index (FWI) reached 28, 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

NASA FIRMS ↗
GWIS · Copernicus ↗

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.

Report an error

What do you think is wrong?

Dates or duration Place or towns Burned area Name It was not a wildfire Same fire as another page Something else

What really happened?

Your connection to the fire (optional) Email (optional)

We will only use your email to reply about this report. Privacy.

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 28 March 2024 to 7 April 2024. 368 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.

Where it burned