How long did the Long fire last?

GWIS (Copernicus) dates it between 28 February 2026 and 7 March 2026: 8 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 1,715 hectares (17.2 km²). It is an estimate: official national figures may differ.

Which municipalities burned?

The fire entered 2 municipalities: Long (1,558 ha, 1.2 %); Den Chai (165 ha, 0.3 %).

What was the weather like?

During the fire the temperature reached 36.5 °C, humidity dropped to 25 % and gusts hit 31 km/h. The fire danger index (FWI) reached 23, 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 · 2026-02-28 → 2026-03-07

Long fire, 28 February 2026 Long, Den Chai

Out · last detection 7 Mar 2026, 19:13 UTC

The fire started on 28 February 2026 in Long, Thailand, and satellites saw it burning for 8 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 1,715 hectares from heat detections, spread across 2 municipalities.

It is the 50th largest in Phrae Province since 2016 (of 120 with a page). Number 464 in Thailand in 2026, of 880.

The power measured by the satellite is low (7.6 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: 1,715ha; GWIS perimeter (Copernicus)
Duration: 8days; 28 Feb 2026 – 7 Mar 2026
Municipalities hit: 2; districts
Started on: 28 Feb; 2026
Heat detections: 22; in a single hotspot: 8 MW
Danger at start: 15; Moderate · FWI index
Energy released: 41MW; sum of detected power

Play back 7 Mar 2026

HOTSPOTS BY DAY 28 Feb7 Mar

How it evolved, day by day

28123567

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

The weather it burned in

36°high

31km/h · peak gust

25%lowest humidity

It had gone one day without rain (1 mm or more) when it started. Rain came after the fire: 3.7 mm on 12 Mar.

This area had burned before

69% of the perimeter overlaps earlier fires recorded since 2016: 461 ha in 2016, 246 ha in 2017, 125 ha in 2018, 225 ha in 2019, 328 ha in 2020, 218 ha in 2021, 209 ha in 2023, 298 ha in 2025. Part of it burned more than once, so the yearly figures add up to more than the 1,189 ha that had burned before.

What happened to each town

Long where it started

1,558 ha reached on 28 Feb

1.2 %
Den Chai

165 ha reached on 1 Mar

0.3 %

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 Feb	35.2 °C	40 %	27 km/h	0.0 mm	Moderate 15
1 Mar	35.6 °C	36 %	28 km/h	0.0 mm	Moderate 18
2 Mar	35.8 °C	25 %	24 km/h	0.0 mm	High 21
3 Mar	35.9 °C	27 %	19 km/h	0.0 mm	High 22
4 Mar	36.5 °C	29 %	23 km/h	0.0 mm	High 23
5 Mar	35.0 °C	43 %	31 km/h	0.1 mm	High 22
6 Mar	34.3 °C	47 %	27 km/h	0.8 mm	Moderate 15
7 Mar	35.4 °C	42 %	20 km/h	0.0 mm	Moderate 17
8 Mar after	36.2 °C	40 %	24 km/h	0.0 mm	Moderate 19
9 Mar after	36.8 °C	37 %	26 km/h	0.0 mm	Moderate 20
10 Mar after	34.3 °C	40 %	25 km/h	0.0 mm	Moderate 21
11 Mar after	33.9 °C	44 %	18 km/h	0.9 mm	Moderate 14
12 Mar after	32.5 °C	46 %	25 km/h	3.7 mm	Very low 4

Before and after, from space

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

↔

Before · 21 Feb 2026

After · 14 Mar 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 4 March 2026 the air beside the fire reached 87 µg/m³ of PM2.5. That day averaged 45: 3.0 times the WHO daily guideline (15).

PM2.5 peak87 µg/m³

Days over the guideline13 days

PM1090 µg/m³

Optical depth1.00

WHO 15

26272812345678910

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 · 22Every 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 Long fire last?: GWIS (Copernicus) dates it between 28 February 2026 and 7 March 2026: 8 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 1,715 hectares (17.2 km²). It is an estimate: official national figures may differ.
Which municipalities burned?: The fire entered 2 municipalities: Long (1,558 ha, 1.2 %); Den Chai (165 ha, 0.3 %).
What was the weather like?: During the fire the temperature reached 36.5 °C, humidity dropped to 25 % and gusts hit 31 km/h. The fire danger index (FWI) reached 23, 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 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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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