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Mae Charim fire, 20 March 2023 แม่จริม · Mae Charim

Out · last detection 27 Mar 2023, 18:43 UTC

The fire started on 20 March 2023 in Mae Charim, Thailand, and satellites saw it burning for 8 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 1,652 hectares from heat detections, spread across a single municipality.

It is the 82th largest in Nan Province since 2016 (of 189 with a page). Number 157 in Thailand in 2023, of 369.

Compare with…

Suggestions: Mae Charim · 2020Mae Charim · 2016Phiang · 2026Phiang · 2023

Burnt area
1,652ha
GWIS perimeter (Copernicus)
Duration
8days
20 Mar 2023 – 27 Mar 2023
Municipalities hit
1
districts
Started on
20 Mar
2023
Heat detections
53
in a single hotspot: 69 MW
Danger at start
5
Low · FWI index
Average daily power
56MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 20 Mar27 Mar
27 Mar 2023

How it evolved, day by day

20 Mar 2023 · 2 MW · 1 21 Mar 2023 · 27 MW · 7 22 Mar 2023 · 8 MW · 3 23 Mar 2023 · 14 MW · 5 24 Mar 2023 · 31 MW · 2 25 Mar 2023 · 105 MW · 17 26 Mar 2023 · 212 MW · 16 27 Mar 2023 · 46 MW · 13
20 Mar 22 Mar 24 Mar 26 Mar

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

The weather it burned in

35°high
52km/h · peak gust
28%lowest humidity

It had gone 2 days without rain (1 mm or more) when it started.

This area had burned before

100% of the perimeter overlaps earlier fires recorded since 2016: 850 ha in 2016, 571 ha in 2017, 1,514 ha in 2019, 1,231 ha in 2020. Part of it burned more than once, so the yearly figures add up to more than the 2,516 ha that had burned before.

How big is it?

10 km
It burned the equivalent of 1% of the area of London (17 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 Charim แม่จริม where it started
    1,810 ha reached on 20 Mar
    1.7 %

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 2025
Built-up area0.21 ha
Residents< 20

Inside the perimeter there were about 0.21 hectares of built-up land and almost nobody lived there (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)
16 Mar 29.4 °C 47 % 20 km/h 1.9 mm Low 5
17 Mar 30.5 °C 48 % 23 km/h 0.4 mm Low 10
18 Mar 31.4 °C 51 % 27 km/h 2.8 mm Very low 3
19 Mar 31.8 °C 43 % 30 km/h 0.6 mm Low 10
20 Mar 32.1 °C 40 % 41 km/h 0.0 mm Moderate 16
21 Mar 33.7 °C 36 % 48 km/h 0.3 mm Moderate 21
22 Mar 34.4 °C 30 % 52 km/h 0.0 mm High 26
23 Mar 34.7 °C 28 % 52 km/h 0.1 mm High 28
24 Mar 34.5 °C 30 % 40 km/h 0.1 mm High 26
25 Mar 34.4 °C 28 % 44 km/h 0.1 mm High 27
26 Mar 33.7 °C 32 % 44 km/h 0.0 mm High 28
27 Mar 34.5 °C 31 % 33 km/h 0.0 mm High 26
28 Mar after 32.9 °C 44 % 37 km/h 0.4 mm High 22
29 Mar after 34.1 °C 31 % 39 km/h 0.1 mm High 26
30 Mar after 32.3 °C 39 % 33 km/h 0.3 mm High 25
31 Mar after 33.4 °C 36 % 37 km/h 0.0 mm High 26
1 Apr after 34.0 °C 35 % 37 km/h 0.0 mm High 27
2 Apr after 35.3 °C 26 % 50 km/h 0.0 mm High 34
3 Apr after 34.7 °C 27 % 48 km/h 0.0 mm High 34
4 Apr after 34.6 °C 29 % 46 km/h 0.0 mm High 34
5 Apr after 34.8 °C 26 % 35 km/h 0.0 mm High 32
6 Apr after 35.2 °C 30 % 27 km/h 0.0 mm High 30
7 Apr after 35.8 °C 29 % 27 km/h 0.0 mm High 30
8 Apr after 33.2 °C 45 % 28 km/h 0.4 mm High 26

Before and after, from space

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

Before · 13 Mar 2023
After · 3 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 144 µg/m³ of PM2.5. That day averaged 72: 4.8 times the WHO daily guideline (15).

PM2.5 peak144 µg/m³
Days over the guideline14 days
PM10206 µg/m³
Optical depth1.32
18192021222324252627282930311
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 · 53Every 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 Charim fire last?
GWIS (Copernicus) dates it between 20 March 2023 and 27 March 2023: 8 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 1,652 hectares (16.5 km²). It is an estimate: official national figures may differ.
Which municipalities burned?
The fire only entered Mae Charim (1,810 ha, 1.7 %).
What was the weather like?
During the fire the temperature reached 34.7 °C, humidity dropped to 28 % and gusts hit 52 km/h. The fire danger index (FWI) reached 28, 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 · 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; 2 polygons grouped in this page.
  • Dates from the perimeter: the VIIRS detections inside it did not change them. 53 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.