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Mae Suai fire, May 2019 แม่สรวย · Mae Suai

Out · last detection 2 May 2019, 19:00 UTC

The fire started on 1 May 2019 in Mae Suai, Thailand, and satellites saw it burning for 4 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 1,025 hectares from heat detections, spread across a single municipality.

It is the 183th largest in Chiang Rai Province since 2016 (of 187 with a page). Number 367 in Thailand in 2019, of 386.

The power measured by the satellite is low (26.3 MW in the strongest hotspot), more typical of grass or stubble burning, or a slow surface fire, than of a large crown fire.

Compare with…

Suggestions: Mae Suai · 2016Phan · 2026Mae Lao · 2026Mae Suai · 2026

Burnt area
1,025ha
GWIS perimeter (Copernicus)
Duration
4days
1 May 2019 – 4 May 2019
Municipalities hit
1
districts
Started on
1 May
2019
Heat detections
27
in a single hotspot: 26 MW
Danger at start
40
Very high · FWI index
Average daily power
108MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 1 May4 May
2 May 2019

How it evolved, day by day

1 May 2019 · 172 MW · 21 2 May 2019 · 45 MW · 6
1 May 2 May

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

The weather it burned in

39°high
36km/h · peak gust
23%lowest humidity

It had gone more than two months without rain (1 mm or more) when it started. Rain came after the fire: 3.0 mm on 13 May.

This area had burned before

86% of the perimeter overlaps earlier fires recorded since 2016: 812 ha in 2016, 85 ha in 2017, 206 ha in 2018. Part of it burned more than once, so the yearly figures add up to more than the 883 ha that had burned before.

How big is it?

10 km
It burned the equivalent of 0.6% of the area of London (10 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. Mae Suai แม่สรวย where it started
    1,030 ha reached on 1 May
    0.7 %

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 area0.22 ha
Residents≈ 20

Inside the perimeter there were about 0.22 hectares of built-up land and about 20 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)
18 Apr 38.9 °C 26 % 31 km/h 0.0 mm Very high 40
19 Apr 39.2 °C 27 % 35 km/h 0.7 mm High 37
20 Apr 38.4 °C 28 % 29 km/h 0.0 mm High 34
21 Apr 37.1 °C 30 % 29 km/h 0.0 mm High 35
22 Apr 36.3 °C 37 % 33 km/h 1.3 mm High 23
23 Apr 37.1 °C 33 % 26 km/h 1.5 mm High 22
24 Apr 36.6 °C 33 % 19 km/h 0.0 mm High 26
25 Apr 36.5 °C 30 % 23 km/h 0.0 mm High 30
26 Apr 37.2 °C 30 % 22 km/h 0.0 mm High 30
27 Apr 36.7 °C 29 % 31 km/h 0.0 mm High 33
28 Apr 38.3 °C 23 % 35 km/h 0.0 mm Very high 40
29 Apr 38.8 °C 24 % 31 km/h 0.0 mm High 38
30 Apr 39.1 °C 26 % 34 km/h 0.0 mm Very high 39
1 May 37.9 °C 29 % 36 km/h 0.0 mm Very high 40
2 May 38.6 °C 28 % 31 km/h 0.0 mm Very high 39
3 May 37.3 °C 35 % 34 km/h 0.0 mm High 38
4 May 38.1 °C 31 % 30 km/h 0.0 mm High 37
5 May after 38.4 °C 27 % 42 km/h 0.0 mm Very high 40
6 May after 38.2 °C 27 % 34 km/h 0.0 mm High 38
7 May after 37.1 °C 30 % 31 km/h 0.0 mm High 36
8 May after 38.6 °C 25 % 33 km/h 0.0 mm Very high 38
9 May after 39.5 °C 21 % 36 km/h 0.0 mm Very high 42
10 May after 38.0 °C 26 % 40 km/h 0.0 mm Very high 42
11 May after 38.7 °C 31 % 26 km/h 0.0 mm High 37
12 May after 37.7 °C 35 % 29 km/h 0.6 mm High 30
13 May after 34.0 °C 46 % 33 km/h 3.0 mm Low 10

Before and after, from space

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

Before · 24 Apr 2019
After · 11 May 2019

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 · 27Every 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 Thailand ›

Frequently asked questions

How long did the Mae Suai fire last?
GWIS (Copernicus) dates it between 1 May 2019 and 4 May 2019: 4 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 1,025 hectares (10.2 km²). It is an estimate: official national figures may differ.
Which municipalities burned?
The fire only entered Mae Suai (1,030 ha, 0.7 %).
What was the weather like?
During the fire the temperature reached 39.2 °C, humidity dropped to 23 % and gusts hit 36 km/h. The fire danger index (FWI) reached 40, 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

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.

Report an error
What do you think is wrong?

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 from the perimeter: the VIIRS detections inside it did not change them. 27 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.