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Xon fire, 27 March 2026 Xon, Phonthong

Out · last detection 18 Apr 2026, 06:57 UTC

The fire started on 27 March 2026 in Xon, Laos, and satellites saw it burning for 23 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 11,662 hectares from heat detections, spread across 2 municipalities.

It is the 8th largest in Houaphan since 2016 (of 132 with a page). Number 31 in Laos in 2026, of 287.

Burnt area
11,662ha
GWIS perimeter (Copernicus)
Duration
23days
27 Mar 2026 – 18 Apr 2026
Municipalities hit
2
districts
Started on
27 Mar
2026
Heat detections
353
in a single hotspot: 328 MW
Danger at start
20
Moderate · FWI index
Energy released
5.6GW
sum of detected power

Where it burned

18 Apr 2026
HOTSPOTS BY DAY 27 Mar18 Apr

How it evolved, day by day

272831123456789101112131415161718

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
57km/h · peak gust
33%lowest humidity

It had gone 11 days without rain (1 mm or more) when it started. Rain came after the fire: 18.1 mm on 19 Apr.

This area had burned before

67% of the perimeter overlaps earlier fires recorded since 2016: 495 ha in 2016, 1,654 ha in 2017, 3,147 ha in 2019, 2,035 ha in 2020, 1,497 ha in 2021, 4,544 ha in 2023, 2,222 ha in 2024. Part of it burned more than once, so the yearly figures add up to more than the 7,790 ha that had burned before.

What happened to each town

  1. Xon where it started
    11,259 ha reached on 27 Mar
    5.4 %
  2. 199 ha reached on 4 Apr
    0.1 %

Burnt area inside each municipality, from crossing the GWIS perimeter with administrative boundaries. The distance is from the town centre 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)
3 Apr 34.4 °C 36 % 51 km/h 0.0 mm Moderate 20
4 Apr 33.4 °C 39 % 47 km/h 0.0 mm Moderate 19
5 Apr 32.6 °C 42 % 55 km/h 0.0 mm High 22
6 Apr 33.1 °C 43 % 51 km/h 0.0 mm High 21
7 Apr 33.3 °C 42 % 49 km/h 0.1 mm High 22
8 Apr 34.4 °C 35 % 45 km/h 0.0 mm High 22
9 Apr 33.7 °C 35 % 53 km/h 0.0 mm High 24
10 Apr 32.6 °C 38 % 54 km/h 0.0 mm High 25
11 Apr 33.1 °C 37 % 57 km/h 0.0 mm High 27
12 Apr 33.6 °C 33 % 44 km/h 0.0 mm High 24
13 Apr 34.6 °C 35 % 42 km/h 0.0 mm High 25
14 Apr 33.4 °C 40 % 41 km/h 0.0 mm High 25
15 Apr 33.7 °C 36 % 43 km/h 0.0 mm High 26
16 Apr 34.2 °C 34 % 38 km/h 0.1 mm High 25
17 Apr 33.4 °C 38 % 34 km/h 0.1 mm High 26
18 Apr 31.5 °C 48 % 34 km/h 0.2 mm High 21
19 Apr after 27.6 °C 70 % 40 km/h 18.1 mm Very low 0

Before and after, from space

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

Before · 20 Mar 2026
After · 25 Apr 2026

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 14 April 2026 the air beside the fire reached 197 µg/m³ of PM2.5. That day averaged 115: 7.6 times the WHO daily guideline (15).

PM2.5 peak197 µg/m³
Days over the guideline28 days
PM10217 µg/m³
Optical depth3.44
25262728293031123456789101112131415161718192021
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 · 353Every 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 Xon fire last?
According to the heat detections seen by satellite inside the perimeter, it burned from 27 March 2026 to 18 April 2026 (23 days). The perimeter dates it from 3 April 2026 to 18 April 2026.
How much area did it burn?
The perimeter GWIS (Copernicus) rebuilt from heat detections is 11,662 hectares (116.6 km²). It is an estimate: official national figures may differ.
Which municipalities burned?
The fire entered 2 municipalities: Xon (11,259 ha, 5.4 %); Phonthong (199 ha, 0.1 %).
What was the weather like?
During the fire the temperature reached 34.6 °C, humidity dropped to 33 % and gusts hit 57 km/h. The fire danger index (FWI) reached 27, 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

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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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.