How long did the Phu Ruea fire last?

GWIS (Copernicus) dates it between 2 April 2026 and 13 April 2026: 12 days between the first and last heat detection of the perimeter.

How much area did it burn?

The perimeter GWIS (Copernicus) rebuilt from heat detections is 3,299 hectares (33.0 km²). It is an estimate: official national figures may differ.

Which municipalities burned?

The fire entered 2 municipalities: Phu Ruea (1,940 ha, 2.8 %); Dan Sai (1,377 ha, 1.0 %).

What was the weather like?

During the fire the temperature reached 32.8 °C, humidity dropped to 25 % and gusts hit 40 km/h. The fire danger index (FWI) reached 35, class High.

Where does this data come from?

From the GWIS (Copernicus) burnt perimeter, NASA FIRMS VIIRS hotspots and the administrative boundaries of Thailand (geoBoundaries). It is not an official report.

TH · Thailand · 2026-04-02 → 2026-04-13

Phu Ruea fire, 2 April 2026 Phu Ruea, Dan Sai

Out · last detection 13 Apr 2026, 06:50 UTC

The fire started on 2 April 2026 in Phu Ruea, Thailand, and satellites saw it burning for 12 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 3,299 hectares from heat detections, spread across 2 municipalities.

It is the 30th largest in Loei Province since 2016 (of 192 with a page). Number 220 in Thailand in 2026, of 880.

The power measured by the satellite is low (25.0 MW in the strongest hotspot), more typical of grass or stubble burning, or a slow surface fire, than of a large crown fire.

Burnt area: 3,299ha; GWIS perimeter (Copernicus)
Duration: 12days; 2 Apr 2026 – 13 Apr 2026
Municipalities hit: 2; districts
Started on: 2 Apr; 2026
Heat detections: 87; in a single hotspot: 25 MW
Danger at start: 21; Moderate · FWI index
Energy released: 372MW; sum of detected power

Play back 13 Apr 2026

HOTSPOTS BY DAY 2 Apr13 Apr

How it evolved, day by day

23458910111213

Fire radiative power detected each day, in megawatts, and number of hotspots. The magenta bar marks the peak day.

The weather it burned in

33°high

40km/h · peak gust

25%lowest humidity

It had gone 30 days without rain (1 mm or more) when it started.

This area had burned before

67% of the perimeter overlaps earlier fires recorded since 2016: 668 ha in 2016, 425 ha in 2017, 1,015 ha in 2019, 621 ha in 2020, 803 ha in 2023, 109 ha in 2024. Part of it burned more than once, so the yearly figures add up to more than the 2,201 ha that had burned before.

What happened to each town

Phu Ruea where it started

1,940 ha reached on 28 Mar

2.8 %
Dan Sai

1,377 ha reached on 28 Mar

1.0 %

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)
28 Mar	31.8 °C	41 %	34 km/h	0.0 mm	Moderate 21
29 Mar	31.6 °C	39 %	37 km/h	1.4 mm	Moderate 17
30 Mar	30.3 °C	47 %	36 km/h	0.2 mm	Moderate 18
31 Mar	31.6 °C	36 %	33 km/h	0.0 mm	High 23
1 Apr	32.1 °C	37 %	26 km/h	0.0 mm	High 21
2 Apr	32.8 °C	34 %	34 km/h	0.0 mm	High 26
3 Apr	32.0 °C	37 %	33 km/h	0.0 mm	High 26
4 Apr	31.3 °C	40 %	31 km/h	0.0 mm	High 26
5 Apr	31.5 °C	41 %	34 km/h	0.0 mm	High 27
6 Apr	32.3 °C	38 %	34 km/h	0.0 mm	High 28
7 Apr	32.3 °C	37 %	35 km/h	0.0 mm	High 29
8 Apr	32.8 °C	31 %	37 km/h	0.0 mm	High 30
9 Apr	32.4 °C	32 %	37 km/h	0.0 mm	High 31
10 Apr	32.8 °C	25 %	38 km/h	0.0 mm	High 34
11 Apr	32.1 °C	34 %	40 km/h	0.0 mm	High 35
12 Apr	32.3 °C	32 %	32 km/h	0.0 mm	High 34
13 Apr	32.4 °C	36 %	32 km/h	0.0 mm	High 32
14 Apr after	33.4 °C	31 %	31 km/h	0.0 mm	High 32
15 Apr after	33.3 °C	31 %	36 km/h	0.0 mm	High 35
16 Apr after	33.6 °C	31 %	31 km/h	0.0 mm	High 34
17 Apr after	33.1 °C	31 %	27 km/h	0.0 mm	High 33
18 Apr after	32.2 °C	40 %	25 km/h	0.0 mm	High 29
19 Apr after	31.7 °C	42 %	38 km/h	0.2 mm	High 31
20 Apr after	31.6 °C	40 %	30 km/h	0.2 mm	High 30
21 Apr after	31.6 °C	41 %	31 km/h	0.1 mm	High 30
22 Apr after	31.9 °C	49 %	33 km/h	0.0 mm	High 27
23 Apr after	31.7 °C	48 %	32 km/h	0.5 mm	High 27

Before and after, from space

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

↔

Before · 26 Mar 2026

After · 20 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 14 April 2026 the air beside the fire reached 76 µg/m³ of PM2.5. That day averaged 49: 3.3 times the WHO daily guideline (15).

PM2.5 peak76 µg/m³

Days over the guideline17 days

PM1082 µg/m³

Optical depth0.92

WHO 15

3112345678910111213141516

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 · 87Every 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 Thailand ›

Frequently asked questions

How long did the Phu Ruea fire last?: GWIS (Copernicus) dates it between 2 April 2026 and 13 April 2026: 12 days between the first and last heat detection of the perimeter.
How much area did it burn?: The perimeter GWIS (Copernicus) rebuilt from heat detections is 3,299 hectares (33.0 km²). It is an estimate: official national figures may differ.
Which municipalities burned?: The fire entered 2 municipalities: Phu Ruea (1,940 ha, 2.8 %); Dan Sai (1,377 ha, 1.0 %).
What was the weather like?: During the fire the temperature reached 32.8 °C, humidity dropped to 25 % and gusts hit 40 km/h. The fire danger index (FWI) reached 35, class High.
Where does this data come from?: From the GWIS (Copernicus) burnt perimeter, NASA FIRMS VIIRS hotspots and the administrative boundaries of Thailand (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.

Emergency number: 199 · 191

Satellite cross-check

NASA FIRMS ↗
GWIS · Copernicus ↗

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 really happened?

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We will only use your email to reply about this report. Privacy. This is not an emergency service: if there is a fire now, call 199 · 191.

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