How long did the Mae Suai fire last?

According to the heat detections seen by satellite inside the perimeter, it burned from 4 April 2019 to 21 April 2019 (18 days). The perimeter dates it from 10 April 2019 to 15 April 2019.

How much area did it burn?

The perimeter GWIS (Copernicus) rebuilt from heat detections is 3,003 hectares (30.0 km²). It is an estimate: official national figures may differ.

Which municipalities burned?

The fire only entered Mae Suai (3,017 ha, 2.1 %).

What was the weather like?

During the fire the temperature reached 38.1 °C, humidity dropped to 20 % and gusts hit 36 km/h. The fire danger index (FWI) reached 43, class Very 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 · 2019-04-04 → 2019-04-21

Mae Suai fire, 4 April 2019 แม่สรวย · Mae Suai

Out · last detection 21 Apr 2019, 19:06 UTC

The fire started on 4 April 2019 in Mae Suai, Thailand, and satellites saw it burning for 18 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 3,003 hectares from heat detections, spread across a single municipality.

It is the 41th largest in Chiang Rai Province since 2016 (of 187 with a page). Number 50 in Thailand in 2019, of 385.

Compare with…

Suggestions: Mae Suai · 2016 Mae Suai · 2026 Mae Suai · 2016 Phrao · 2026

Burnt area: 3,003ha; GWIS perimeter (Copernicus)
Duration: 18days; 4 Apr 2019 – 21 Apr 2019
Municipalities hit: 1; districts
Started on: 4 Apr; 2019
Heat detections: 100; in a single hotspot: 50 MW
Danger at start: 35; High · FWI index
Average daily power: 37MW; detected power per day, on average

HOTSPOTS BY DAY 4 Apr21 Apr

Play back 21 Apr 2019

How it evolved, day by day

4 Apr 8 Apr 11 Apr 13 Apr 15 Apr 21 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

38°high

36km/h · peak gust

20%lowest humidity

It had gone 45 days without rain (1 mm or more) when it started. Rain came after the fire: 5.0 mm on 19 Apr.

This area had burned before

22% of the perimeter overlaps earlier fires recorded since 2016: 867 ha in 2016. Part of it burned more than once, so the yearly figures add up to more than the 670 ha that had burned before.

29 ha Mae Suai fire, April 2016 1,579 ha in total; the hectares shown are those it shares with this fire

How big is it?

It burned the equivalent of 1.9% of the area of London (30 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

Mae Suai แม่สรวย where it started

3,017 ha reached on 4 Apr

2.1 %

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 2020

Built-up area1.1 ha

Residents≈ 100

Inside the perimeter there were about 1.1 hectares of built-up land and about 100 residents (GHSL 2020, 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.

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)
30 Mar	34.9 °C	25 %	20 km/h	0.0 mm	High 35
31 Mar	35.2 °C	29 %	34 km/h	0.0 mm	Very high 39
1 Apr	36.0 °C	20 %	32 km/h	0.0 mm	Very high 39
2 Apr	35.5 °C	25 %	30 km/h	0.0 mm	Very high 39
3 Apr	35.3 °C	28 %	28 km/h	0.0 mm	High 37
4 Apr	36.1 °C	24 %	23 km/h	0.0 mm	High 36
5 Apr	36.0 °C	24 %	24 km/h	0.0 mm	High 38
6 Apr	35.5 °C	29 %	27 km/h	0.0 mm	High 37
7 Apr	36.4 °C	25 %	35 km/h	0.0 mm	Very high 40
8 Apr	37.0 °C	21 %	36 km/h	0.0 mm	Very high 40
9 Apr	36.7 °C	25 %	32 km/h	0.0 mm	Very high 39
10 Apr	37.2 °C	23 %	36 km/h	0.0 mm	Very high 42
11 Apr	37.5 °C	22 %	27 km/h	0.0 mm	Very high 39
12 Apr	37.1 °C	26 %	27 km/h	0.0 mm	Very high 38
13 Apr	37.7 °C	24 %	30 km/h	0.0 mm	Very high 41
14 Apr	38.0 °C	23 %	35 km/h	0.0 mm	Very high 43
15 Apr	38.1 °C	23 %	35 km/h	0.0 mm	Very high 43
16 Apr	38.5 °C	25 %	28 km/h	0.0 mm	Very high 39
17 Apr	37.3 °C	29 %	30 km/h	0.0 mm	Very high 39
18 Apr	38.6 °C	27 %	25 km/h	0.0 mm	High 37
19 Apr	38.4 °C	28 %	35 km/h	5.0 mm	Moderate 17

Before and after, from space

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

↔

Before · 28 Mar 2019

After · 28 Apr 2019

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.

Detections table · 100Every 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 Mae Suai fire last?: According to the heat detections seen by satellite inside the perimeter, it burned from 4 April 2019 to 21 April 2019 (18 days). The perimeter dates it from 10 April 2019 to 15 April 2019.
How much area did it burn?: The perimeter GWIS (Copernicus) rebuilt from heat detections is 3,003 hectares (30.0 km²). It is an estimate: official national figures may differ.
Which municipalities burned?: The fire only entered Mae Suai (3,017 ha, 2.1 %).
What was the weather like?: During the fire the temperature reached 38.1 °C, humidity dropped to 20 % and gusts hit 36 km/h. The fire danger index (FWI) reached 43, class Very 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 · Emergency number and official warnings ›

Satellite cross-check

NASA FIRMS ↗
GWIS · Copernicus ↗

History of this page · 2 Changes in area, dates, name, official record or merged pages, compared every night since 24 October 2026.

26 October 2026 Last day with fire: 15 April 2019 → 21 April 2019.
26 October 2026 Start date: 10 April 2019 → 4 April 2019.

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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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.

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 10 April 2019 to 15 April 2019. 100 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 2020, 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