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Mae Chan fire, March 2023 แม่จัน · Mae Chan, Mueang Chiang Rai, Mae Fa Luang

Out · last detection 20 Apr 2023, 07:04 UTC

The fire started on 22 March 2023 in Mae Chan, Thailand, and satellites saw it burning for 29 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 17,804 hectares from heat detections, spread across 3 municipalities.

It is the 3th largest in Chiang Rai Province since 2016 (of 187 with a page). Number 3 in Thailand in 2023, of 369.

Compare with…

Suggestions: Mueang Chiang Rai · 2020Mueang Chiang Rai · 2019Mueang Chiang Rai · 2019Mae Chan · 2020

Burnt area
17,804ha
GWIS perimeter (Copernicus)
Duration
29days
22 Mar 2023 – 19 Apr 2023
Municipalities hit
3
districts
Started on
22 Mar
2023
Heat detections
865
in a single hotspot: 65 MW
Danger at start
6
Low · FWI index
Average daily power
145MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 22 Mar19 Apr
20 Apr 2023

How it evolved, day by day

22 Mar 2023 · 26 MW · 11 23 Mar 2023 · 177 MW · 42 24 Mar 2023 · 59 MW · 27 25 Mar 2023 · 226 MW · 54 26 Mar 2023 · 307 MW · 78 27 Mar 2023 · 104 MW · 38 28 Mar 2023 · 179 MW · 56 29 Mar 2023 · 127 MW · 44 30 Mar 2023 · 190 MW · 41 31 Mar 2023 · 172 MW · 33 1 Apr 2023 · 132 MW · 42 2 Apr 2023 · 52 MW · 8 3 Apr 2023 · 33 MW · 13 4 Apr 2023 · 122 MW · 24 5 Apr 2023 · 422 MW · 59 6 Apr 2023 · 97 MW · 20 7 Apr 2023 · 91 MW · 23 8 Apr 2023 · 79 MW · 13 9 Apr 2023 · 37 MW · 10 10 Apr 2023 · 72 MW · 6 11 Apr 2023 · 10 MW · 3 12 Apr 2023 · 74 MW · 18 13 Apr 2023 · 106 MW · 14 14 Apr 2023 · 193 MW · 27 15 Apr 2023 · 155 MW · 33 16 Apr 2023 · 308 MW · 48 17 Apr 2023 · 346 MW · 34 18 Apr 2023 · 91 MW · 7 19 Apr 2023 · 340 MW · 32 20 Apr 2023 · 27 MW · 3
22 Mar 27 Mar 1 Apr 5 Apr 6 Apr 11 Apr 16 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

41°high
38km/h · peak gust
20%lowest humidity

It had gone 0 days without rain (1 mm or more) when it started. Rain came after the fire: 2.0 mm on 22 Apr.

This area had burned before

89% of the perimeter overlaps earlier fires recorded since 2016: 6,538 ha in 2016, 14,639 ha in 2019, 10,799 ha in 2020. Part of it burned more than once, so the yearly figures add up to more than the 15,773 ha that had burned before.

How big is it?

10 km
It burned the equivalent of 11% of the area of London (178 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 Chan แม่จัน where it started
    9,491 ha
    13 %
  2. Mueang Chiang Rai เมืองเชียงราย
    7,117 ha
    4.5 %
  3. Mae Fa Luang แม่ฟ้าหลวง
    1,291 ha
    2.0 %

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 area20 ha
Residents≈ 1,700

Inside the perimeter there were about 20 hectares of built-up land and about 1,700 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)
18 Mar 32.2 °C 43 % 21 km/h 0.1 mm Low 6
19 Mar 33.9 °C 36 % 27 km/h 0.0 mm Moderate 14
20 Mar 33.2 °C 41 % 30 km/h 2.0 mm Low 7
21 Mar 33.8 °C 37 % 30 km/h 0.1 mm Moderate 14
22 Mar 35.8 °C 26 % 35 km/h 0.0 mm High 22
23 Mar 35.6 °C 27 % 31 km/h 0.0 mm Moderate 21
24 Mar 34.7 °C 31 % 26 km/h 0.0 mm Moderate 21
25 Mar 34.6 °C 31 % 27 km/h 0.0 mm High 22
26 Mar 36.0 °C 26 % 24 km/h 0.0 mm High 23
27 Mar 34.8 °C 32 % 26 km/h 0.0 mm High 25
28 Mar 36.7 °C 24 % 38 km/h 0.0 mm High 29
29 Mar 34.9 °C 27 % 32 km/h 0.0 mm High 27
30 Mar 35.9 °C 27 % 24 km/h 0.0 mm High 27
31 Mar 36.1 °C 27 % 24 km/h 0.0 mm High 27
1 Apr 36.6 °C 30 % 31 km/h 0.0 mm High 30
2 Apr 36.5 °C 26 % 35 km/h 0.0 mm High 32
3 Apr 35.2 °C 27 % 35 km/h 0.0 mm High 33
4 Apr 36.8 °C 22 % 30 km/h 0.0 mm High 32
5 Apr 36.9 °C 20 % 21 km/h 0.0 mm High 33
6 Apr 36.3 °C 27 % 27 km/h 0.0 mm High 36
7 Apr 37.0 °C 30 % 24 km/h 0.0 mm High 34
8 Apr 37.0 °C 33 % 28 km/h 0.0 mm High 33
9 Apr 38.2 °C 29 % 31 km/h 0.0 mm High 33
10 Apr 38.9 °C 26 % 25 km/h 0.0 mm High 32
11 Apr 39.1 °C 26 % 19 km/h 0.0 mm High 32
12 Apr 39.2 °C 22 % 18 km/h 0.0 mm High 34
13 Apr 39.4 °C 28 % 22 km/h 0.0 mm High 35
14 Apr 40.2 °C 22 % 19 km/h 0.0 mm High 36
15 Apr 39.0 °C 24 % 23 km/h 0.0 mm High 38
16 Apr 39.7 °C 26 % 28 km/h 0.0 mm High 38
17 Apr 38.7 °C 32 % 27 km/h 0.0 mm Very high 39
18 Apr 40.6 °C 26 % 24 km/h 0.0 mm High 35
19 Apr 40.3 °C 24 % 27 km/h 0.0 mm High 37
20 Apr after 39.9 °C 26 % 26 km/h 0.8 mm High 34
21 Apr after 38.4 °C 30 % 28 km/h 0.6 mm High 33
22 Apr after 37.0 °C 35 % 30 km/h 2.0 mm Moderate 20

Before and after, from space

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

Before · 15 Mar 2023
After · 26 Apr 2023

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 27 March 2023 the air beside the fire reached 185 µg/m³ of PM2.5. That day averaged 107: 7.1 times the WHO daily guideline (15).

PM2.5 peak185 µg/m³
Days over the guideline34 days
PM10265 µg/m³
Optical depth1.88
20212223242526272829303112345678910111213141516171819202122
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 · 865Every 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 Chan fire last?
GWIS (Copernicus) dates it between 22 March 2023 and 19 April 2023: 29 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 17,804 hectares (178.0 km²). It is an estimate: official national figures may differ.
Which municipalities burned?
The fire entered 3 municipalities: Mae Chan (9,491 ha, 13 %); Mueang Chiang Rai (7,117 ha, 4.5 %); Mae Fa Luang (1,291 ha, 2.0 %).
What was the weather like?
During the fire the temperature reached 40.6 °C, humidity dropped to 20 % and gusts hit 38 km/h. The fire danger index (FWI) reached 39, 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; 5 polygons grouped in this page.
  • Dates from the perimeter: the VIIRS detections inside it did not change them. 865 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.