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Mae Chaem fire, 2 April 2026 แม่แจ่ม · Mae Chaem

Out · last detection 10 Apr 2026, 06:06 UTC

The fire started on 2 April 2026 in Mae Chaem, Thailand, and satellites saw it burning for 9 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 2,304 hectares from heat detections, spread across a single municipality.

It is the 117th largest in Chiang Mai Province since 2016 (of 449 with a page). Number 275 in Thailand in 2026, of 811.

The power measured by the satellite is low (12.2 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 Chaem · 2024Mae Chaem · 2020

Burnt area
2,304ha
GWIS perimeter (Copernicus)
Duration
9days
2 Apr 2026 – 10 Apr 2026
Municipalities hit
1
districts
Started on
2 Apr
2026
Heat detections
44
in a single hotspot: 12 MW
Danger at start
23
High · FWI index
Average daily power
26MW
detected power per day, on average

Where it burned

10 Apr 2026
HOTSPOTS BY DAY 2 Apr10 Apr

How it evolved, day by day

2 Apr 2026 · 37 MW · 12 3 Apr 2026 · 8 MW · 6 4 Apr 2026 · 8 MW · 3 7 Apr 2026 · 24 MW · 5 8 Apr 2026 · 6 MW · 2 9 Apr 2026 · 30 MW · 9 10 Apr 2026 · 68 MW · 7
2 Apr 3 Apr 4 Apr 7 Apr 8 Apr 9 Apr 10 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

36°high
50km/h · peak gust
27%lowest humidity

It had gone 11 days without rain (1 mm or more) when it started.

This area had burned before

80% of the perimeter overlaps earlier fires recorded since 2016: 981 ha in 2016, 67 ha in 2017, 838 ha in 2019, 669 ha in 2020, 235 ha in 2021, 460 ha in 2023, 531 ha in 2024, 31 ha in 2025. Part of it burned more than once, so the yearly figures add up to more than the 1,842 ha that had burned before.

How big is it?

10 km
It burned the equivalent of 1.5% of the area of London (23 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 Chaem แม่แจ่ม where it started
    2,318 ha
    0.8 %

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)
29 Mar 34.4 °C 27 % 50 km/h 0.0 mm High 23
30 Mar 34.1 °C 34 % 43 km/h 0.0 mm High 23
31 Mar 34.2 °C 39 % 37 km/h 0.2 mm Moderate 20
1 Apr 34.1 °C 39 % 31 km/h 0.0 mm Moderate 20
2 Apr 35.2 °C 34 % 37 km/h 0.0 mm High 22
3 Apr 35.6 °C 34 % 37 km/h 0.0 mm High 23
4 Apr 34.0 °C 41 % 32 km/h 0.0 mm High 22
5 Apr 34.3 °C 44 % 38 km/h 0.1 mm High 22
6 Apr 33.3 °C 45 % 32 km/h 0.0 mm Moderate 21
7 Apr 32.8 °C 46 % 41 km/h 1.0 mm Moderate 16
8 Apr 34.4 °C 33 % 45 km/h 0.0 mm High 25
9 Apr 33.3 °C 37 % 44 km/h 0.0 mm High 25
10 Apr 33.4 °C 38 % 46 km/h 0.0 mm High 26
11 Apr after 33.7 °C 37 % 46 km/h 0.0 mm High 27
12 Apr after 34.1 °C 37 % 36 km/h 0.0 mm High 25
13 Apr after 35.0 °C 38 % 37 km/h 0.1 mm High 26
14 Apr after 35.3 °C 37 % 34 km/h 0.0 mm High 26
15 Apr after 35.5 °C 32 % 41 km/h 0.0 mm High 29
16 Apr after 34.6 °C 38 % 32 km/h 0.0 mm High 28
17 Apr after 34.6 °C 39 % 26 km/h 0.3 mm High 26
18 Apr after 34.6 °C 42 % 30 km/h 0.2 mm High 26
19 Apr after 34.1 °C 38 % 44 km/h 0.3 mm High 30
20 Apr after 33.4 °C 42 % 41 km/h 0.1 mm High 29

Before and after, from space

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

Before · 26 Mar 2026
After · 17 Apr 2026

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 12 April 2026 the air beside the fire reached 79 µg/m³ of PM2.5. That day averaged 57: 3.8 times the WHO daily guideline (15).

PM2.5 peak79 µg/m³
Days over the guideline17 days
PM1092 µg/m³
Optical depth1.46
272829303112345678910111213
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 · 44Every 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 Chaem fire last?
GWIS (Copernicus) dates it between 2 April 2026 and 10 April 2026: 9 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 2,304 hectares (23.0 km²). It is an estimate: official national figures may differ.
Which municipalities burned?
The fire only entered Mae Chaem (2,318 ha, 0.8 %).
What was the weather like?
During the fire the temperature reached 35.6 °C, humidity dropped to 27 % and gusts hit 50 km/h. The fire danger index (FWI) reached 26, 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

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; 2 polygons grouped in this page.
  • Dates from the perimeter: the VIIRS detections inside it did not change them. 44 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.

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.