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Pek fire, 21 March 2026 Pek, Khoune

Out · last detection 11 Apr 2026, 05:47 UTC

The fire started on 21 March 2026 in Pek, Laos, and satellites saw it burning for 21 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 9,358 hectares from heat detections, spread across 2 municipalities.

It is the 9th largest in Xiangkhouang since 2016 (of 109 with a page). Number 40 in Laos in 2026, of 308.

Compare with…
Burnt area
9,358ha
GWIS perimeter (Copernicus)
Duration
21days
21 Mar 2026 – 10 Apr 2026
Municipalities hit
2
districts
Started on
21 Mar
2026
Heat detections
162
in a single hotspot: 140 MW
Danger at start
1
Very low · FWI index
Average daily power
135MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 21 Mar10 Apr
11 Apr 2026

How it evolved, day by day

21 Mar 2026 · 17 MW · 1 24 Mar 2026 · 23 MW · 5 25 Mar 2026 · 45 MW · 4 26 Mar 2026 · 329 MW · 25 27 Mar 2026 · 711 MW · 46 28 Mar 2026 · 243 MW · 19 29 Mar 2026 · 151 MW · 11 30 Mar 2026 · 13 MW · 1 1 Apr 2026 · 20 MW · 3 2 Apr 2026 · 26 MW · 4 3 Apr 2026 · 56 MW · 9 5 Apr 2026 · 76 MW · 1 6 Apr 2026 · 171 MW · 5 8 Apr 2026 · 65 MW · 12 9 Apr 2026 · 285 MW · 11 10 Apr 2026 · 66 MW · 4 11 Apr 2026 · 3 MW · 1
21 Mar 26 Mar 27 Mar 29 Mar 2 Apr 6 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

31°high
51km/h · peak gust
27%lowest humidity

It had gone 3 days without rain (1 mm or more) when it started. Rain came after the fire: 1.7 mm on 18 Apr.

This area had burned before

85% of the perimeter overlaps earlier fires recorded since 2016: 524 ha in 2016, 3,010 ha in 2017, 635 ha in 2018, 4,930 ha in 2020, 252 ha in 2022, 2,557 ha in 2023, 4,572 ha in 2024, 1,721 ha in 2025. Part of it burned more than once, so the yearly figures add up to more than the 7,917 ha that had burned before.

How big is it?

10 km
It burned the equivalent of 5.9% of the area of London (94 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. Pek where it started
    4,928 ha
    3.9 %
  2. 4,481 ha
    2.5 %

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 area0.62 ha
Residents≈ 600

Inside the perimeter there were about 0.62 hectares of built-up land and about 600 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)
21 Mar 25.9 °C 60 % 24 km/h 1.9 mm Very low 1
22 Mar 25.3 °C 65 % 36 km/h 2.5 mm Very low 0
23 Mar 27.1 °C 51 % 34 km/h 0.5 mm Very low 2
24 Mar 28.2 °C 43 % 30 km/h 0.0 mm Low 5
25 Mar 27.3 °C 62 % 36 km/h 2.9 mm Very low 1
26 Mar 28.5 °C 46 % 35 km/h 0.1 mm Very low 4
27 Mar 28.2 °C 46 % 40 km/h 0.0 mm Low 7
28 Mar 27.9 °C 48 % 34 km/h 0.7 mm Low 6
29 Mar 27.8 °C 48 % 51 km/h 1.0 mm Low 6
30 Mar 25.9 °C 52 % 46 km/h 0.4 mm Low 8
31 Mar 27.1 °C 47 % 40 km/h 0.0 mm Low 8
1 Apr 26.8 °C 53 % 30 km/h 0.2 mm Low 8
2 Apr 27.7 °C 52 % 41 km/h 0.0 mm Low 10
3 Apr 28.4 °C 46 % 42 km/h 0.0 mm Low 11
4 Apr 27.5 °C 48 % 42 km/h 0.0 mm Low 11
5 Apr 27.1 °C 51 % 49 km/h 0.0 mm Moderate 12
6 Apr 28.8 °C 49 % 45 km/h 0.0 mm Moderate 12
7 Apr 29.3 °C 44 % 41 km/h 0.0 mm Moderate 13
8 Apr 30.6 °C 32 % 40 km/h 0.0 mm Moderate 17
9 Apr 31.3 °C 27 % 43 km/h 0.0 mm Moderate 21
10 Apr 30.7 °C 28 % 46 km/h 0.0 mm High 22
11 Apr after 30.6 °C 33 % 49 km/h 0.0 mm High 23
12 Apr after 30.8 °C 34 % 36 km/h 0.0 mm High 21
13 Apr after 30.9 °C 36 % 34 km/h 0.0 mm High 22
14 Apr after 29.7 °C 40 % 30 km/h 0.0 mm Moderate 19
15 Apr after 30.6 °C 36 % 33 km/h 0.0 mm Moderate 20
16 Apr after 32.3 °C 25 % 30 km/h 0.0 mm High 23
17 Apr after 29.4 °C 37 % 31 km/h 0.0 mm High 22
18 Apr after 27.5 °C 51 % 31 km/h 1.7 mm Low 6

Before and after, from space

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

Before · 14 Mar 2026
After · 17 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 13 April 2026 the air beside the fire reached 213 µg/m³ of PM2.5. That day averaged 122: 8.1 times the WHO daily guideline (15).

PM2.5 peak213 µg/m³
Days over the guideline26 days
PM10228 µg/m³
Optical depth2.19
1920212223242526272829303112345678910111213
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 · 162Every 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 Pek fire last?
According to the heat detections seen by satellite inside the perimeter, it burned from 21 March 2026 to 10 April 2026 (21 days). The perimeter dates it from 24 March 2026 to 3 April 2026.
How much area did it burn?
The perimeter GWIS (Copernicus) rebuilt from heat detections is 9,358 hectares (93.6 km²). It is an estimate: official national figures may differ.
Which municipalities burned?
The fire entered 2 municipalities: Pek (4,928 ha, 3.9 %); Khoune (4,481 ha, 2.5 %).
What was the weather like?
During the fire the temperature reached 31.3 °C, humidity dropped to 27 % and gusts hit 51 km/h. The fire danger index (FWI) reached 22, 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 24 March 2026 to 3 April 2026. 162 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.