Mae Chaem fire, 22 April 2018 แม่แจ่ม · Mae Chaem
The fire started on 22 April 2018 in Mae Chaem, Thailand, and satellites saw it burning for 2 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 1,865 hectares from heat detections, spread across a single municipality.
It is the 150th largest in Chiang Mai Province since 2016 (of 399 with a page). Number 35 in Thailand in 2018, of 84.
The power measured by the satellite is low (26.0 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 · 2016Hang Dong · 2016Samoeng · 2020
- Burnt area
- 1,865ha
- GWIS perimeter (Copernicus)
- Duration
- 2days
- 22 Apr 2018 – 23 Apr 2018
- Municipalities hit
- 1
- districts
- Started on
- 22 Apr
- 2018
- Heat detections
- 50
- in a single hotspot: 26 MW
- Danger at start
- 18
- Moderate · FWI index
- Average daily power
- 217MW
- detected power per day, on average
Where it burned
How it evolved, day by day
Fire radiative power detected each day, in megawatts, and number of hotspots. The magenta bar marks the peak day.
The weather it burned in
It had gone 4 days without rain (1 mm or more) when it started. Rain came after the fire: 2.4 mm on 24 Apr.
This area had burned before
72% of the perimeter overlaps earlier fires recorded since 2016: 1,114 ha in 2016, 525 ha in 2017. Part of it burned more than once, so the yearly figures add up to more than the 1,350 ha that had burned before.
How big is it?
London boundary: geoBoundaries · Office for National Statistics (Open Government Licence v3.0).
Bangkok boundary: geoBoundaries · OpenStreetMap, Wambacher · © OpenStreetMap contributors (ODbL 1.0).
Paris boundary: geoBoundaries · Institut national de l'information géographique et forestière (IGN-F) (Etalab Open License 2.0).
Madrid boundary: geoBoundaries · Open Data ESRI, IGN Central Registry of Cartography Area (CC BY 4.0).
This compares size, not location: both shapes are at the same scale, north up, centred on each other.
What happened to each town
-
1,877 ha0.7 %
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.
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) |
|---|---|---|---|---|---|
| 22 Apr | 34.6 °C | 43 % | 31 km/h | 0.0 mm | Moderate 18 |
| 23 Apr | 36.3 °C | 41 % | 27 km/h | 0.0 mm | Moderate 17 |
| 24 Apr after | 35.0 °C | 45 % | 29 km/h | 2.4 mm | Low 7 |
Before and after, from space
Drag the line to compare the same ground before the fire and after it.
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 · 50Every satellite heat detection, one by one, with time, satellite, power and coordinates.
| Date and time | Satellite | FRP (MW) | Lat | Lon |
|---|
Other fires nearby
Frequently asked questions
- How long did the Mae Chaem fire last?
- GWIS (Copernicus) dates it between 22 April 2018 and 23 April 2018: 2 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 1,865 hectares (18.6 km²). It is an estimate: official national figures may differ.
- Which municipalities burned?
- The fire only entered Mae Chaem (1,877 ha, 0.7 %).
- What was the weather like?
- During the fire the temperature reached 36.3 °C, humidity dropped to 41 % and gusts hit 31 km/h. The fire danger index (FWI) reached 18, class Moderate.
- 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.
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
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. 50 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.
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.