How long did the Sanamxay fire last?

According to the heat detections seen by satellite inside the perimeter, it burned from 23 March 2026 to 12 April 2026 (21 days). The perimeter dates it from 26 March 2026 to 5 April 2026.

How much area did it burn?

The perimeter GWIS (Copernicus) rebuilt from heat detections is 2,608 hectares (26.1 km²). It is an estimate: official national figures may differ.

Which municipalities burned?

The fire entered 2 municipalities: Sanamxay (1,784 ha, 0.8 %); Phouvong (839 ha, 0.2 %).

What was the weather like?

During the fire the temperature reached 39.5 °C, humidity dropped to 27 % and gusts hit 34 km/h. The fire danger index (FWI) reached 33, 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 · 2026-03-23 → 2026-04-12

Sanamxay fire, March 2026 Sanamxay, Phouvong

Out · last detection 12 Apr 2026, 07:08 UTC

The fire started on 23 March 2026 in Sanamxay, Laos, and satellites saw it burning for 21 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 2,608 hectares from heat detections, spread across 2 municipalities.

It is the 17th largest in Attapeu since 2016 (of 37 with a page). Number 201 in Laos in 2026, of 308.

Compare with…

Suggestions: Phouvong · 2024 Phouvong · 2023 Sanamxay · 2024 Sanamxay · 2022

Burnt area: 2,608ha; GWIS perimeter (Copernicus)
Duration: 21days; 23 Mar 2026 – 12 Apr 2026
Municipalities hit: 2; districts
Started on: 23 Mar; 2026
Heat detections: 75; in a single hotspot: 214 MW
Danger at start: 23; High · FWI index
Average daily power: 117MW; detected power per day, on average

HOTSPOTS BY DAY 23 Mar12 Apr

Play back 12 Apr 2026

How it evolved, day by day

24 Mar 27 Mar 30 Mar 2 Apr 5 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

40°high

34km/h · peak gust

27%lowest humidity

It had gone 2 days without rain (1 mm or more) when it started. Rain came after the fire: 1.2 mm on 20 Apr.

This area had burned before

38% of the perimeter overlaps earlier fires recorded since 2016: 110 ha in 2020, 712 ha in 2024, 228 ha in 2025. Part of it burned more than once, so the yearly figures add up to more than the 998 ha that had burned before.

How big is it?

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

Sanamxay where it started

1,784 ha reached on 24 Mar

0.8 %
Phouvong

839 ha reached on 25 Mar

0.2 %

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 area1.9 ha

Residents≈ 650

Inside the perimeter there were about 1.9 hectares of built-up land and about 650 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	37.4 °C	31 %	26 km/h	0.0 mm	High 23
24 Mar	38.9 °C	28 %	24 km/h	0.0 mm	High 25
25 Mar	39.3 °C	27 %	22 km/h	0.0 mm	High 26
26 Mar	39.3 °C	27 %	23 km/h	0.0 mm	High 28
27 Mar	38.9 °C	29 %	25 km/h	0.0 mm	High 29
28 Mar	39.5 °C	29 %	19 km/h	0.0 mm	High 28
29 Mar	38.4 °C	31 %	23 km/h	0.0 mm	High 29
30 Mar	39.0 °C	29 %	26 km/h	0.1 mm	High 30
31 Mar	39.0 °C	27 %	28 km/h	0.0 mm	High 31
1 Apr	39.1 °C	29 %	22 km/h	0.0 mm	High 31
2 Apr	38.3 °C	34 %	26 km/h	0.0 mm	High 30
3 Apr	37.9 °C	35 %	31 km/h	0.0 mm	High 32
4 Apr	36.9 °C	38 %	31 km/h	0.2 mm	High 31
5 Apr	38.0 °C	35 %	33 km/h	0.0 mm	High 32
6 Apr	38.8 °C	32 %	34 km/h	0.0 mm	High 32
7 Apr	38.0 °C	34 %	32 km/h	0.0 mm	High 33
8 Apr	39.5 °C	31 %	27 km/h	0.0 mm	High 31
9 Apr	38.2 °C	35 %	29 km/h	0.0 mm	High 31
10 Apr	37.4 °C	39 %	30 km/h	0.0 mm	High 31
11 Apr	37.6 °C	39 %	33 km/h	0.0 mm	High 32
12 Apr	38.7 °C	35 %	30 km/h	0.0 mm	High 31
13 Apr after	37.8 °C	38 %	27 km/h	0.0 mm	High 31
14 Apr after	38.8 °C	37 %	24 km/h	0.0 mm	High 30
15 Apr after	37.5 °C	42 %	27 km/h	0.4 mm	High 30
16 Apr after	36.5 °C	44 %	23 km/h	0.3 mm	High 27
17 Apr after	36.2 °C	48 %	28 km/h	0.8 mm	Moderate 20
18 Apr after	37.3 °C	44 %	23 km/h	0.8 mm	High 22
19 Apr after	34.6 °C	52 %	24 km/h	0.1 mm	Moderate 21
20 Apr after	36.2 °C	44 %	26 km/h	1.2 mm	Moderate 19

Before and after, from space

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

↔

Before · 16 Mar 2026

After · 19 Apr 2026

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 28 March 2026 the air beside the fire reached 106 µg/m³ of PM2.5. That day averaged 66: 4.4 times the WHO daily guideline (15).

PM2.5 peak106 µg/m³

Days over the guideline26 days

PM10109 µg/m³

Optical depth1.37

WHO 15

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 · 75Every 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 Sanamxay fire last?: According to the heat detections seen by satellite inside the perimeter, it burned from 23 March 2026 to 12 April 2026 (21 days). The perimeter dates it from 26 March 2026 to 5 April 2026.
How much area did it burn?: The perimeter GWIS (Copernicus) rebuilt from heat detections is 2,608 hectares (26.1 km²). It is an estimate: official national figures may differ.
Which municipalities burned?: The fire entered 2 municipalities: Sanamxay (1,784 ha, 0.8 %); Phouvong (839 ha, 0.2 %).
What was the weather like?: During the fire the temperature reached 39.5 °C, humidity dropped to 27 % and gusts hit 34 km/h. The fire danger index (FWI) reached 33, 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.

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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?

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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 26 March 2026 to 5 April 2026. 75 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