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TH · Thailand · –

San Kamphaeng fire, March 2023 สันกำแพง · San Kamphaeng, Mae On

Out · last detection 1 Apr 2023, 18:50 UTC

The fire started on 24 March 2023 in San Kamphaeng, Thailand, and satellites saw it burning for 9 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 1,474 hectares from heat detections, spread across 2 municipalities.

It is the 153th largest in Chiang Mai Province since 2016 (of 319 with a page). Number 190 in Thailand in 2023, of 369.

The power measured by the satellite is low (13.3 MW in the strongest hotspot), more typical of grass or stubble burning, or a slow surface fire, than of a large crown fire.

Burnt area
1,474ha
GWIS perimeter (Copernicus)
Duration
9days
24 Mar 2023 – 1 Apr 2023
Municipalities hit
2
districts
Started on
24 Mar
2023
Heat detections
39
in a single hotspot: 13 MW
Danger at start
34
High · FWI index
Average daily power
25MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 24 Mar1 Apr
1 Apr 2023

How it evolved, day by day

26 Mar 2023 · 2 MW · 1 27 Mar 2023 · 11 MW · 5 28 Mar 2023 · 55 MW · 12 29 Mar 2023 · 69 MW · 12 30 Mar 2023 · 30 MW · 5 31 Mar 2023 · 2 MW · 1 1 Apr 2023 · 4 MW · 3
26 Mar 29 Mar 1 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

38°high
38km/h · peak gust
21%lowest humidity

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

This area had burned before

98% of the perimeter overlaps earlier fires recorded since 2016: 975 ha in 2016, 576 ha in 2017, 140 ha in 2018, 497 ha in 2019, 770 ha in 2020, 931 ha in 2021, 745 ha in 2022. Part of it burned more than once, so the yearly figures add up to more than the 1,446 ha that had burned before.

How big is it?

10 km
It burned the equivalent of 0.9% of the area of London (15 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. San Kamphaeng สันกำแพง where it started
    1,048 ha reached on 26 Mar
    4.4 %
  2. Mae On แม่ออน
    434 ha reached on 28 Mar
    0.9 %

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 area< 0.1 ha
Residents< 20

Inside the perimeter there was no noticeable 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)
24 Mar 35.4 °C 30 % 33 km/h 0.0 mm High 34
25 Mar 35.5 °C 28 % 33 km/h 0.1 mm High 35
26 Mar 35.3 °C 31 % 32 km/h 0.0 mm High 35
27 Mar 36.2 °C 29 % 31 km/h 0.0 mm High 33
28 Mar 37.5 °C 21 % 38 km/h 0.0 mm Very high 42
29 Mar 36.3 °C 26 % 37 km/h 0.0 mm Very high 44
30 Mar 35.6 °C 31 % 32 km/h 0.0 mm Very high 39
31 Mar 35.7 °C 32 % 29 km/h 0.1 mm High 36
1 Apr 35.9 °C 34 % 32 km/h 0.0 mm High 36
2 Apr after 37.0 °C 26 % 42 km/h 0.0 mm Very high 43
3 Apr after 35.6 °C 31 % 39 km/h 0.0 mm Very high 42
4 Apr after 36.1 °C 29 % 33 km/h 0.0 mm Very high 41
5 Apr after 36.8 °C 24 % 27 km/h 0.0 mm High 36
6 Apr after 37.1 °C 28 % 23 km/h 0.0 mm High 36
7 Apr after 37.3 °C 31 % 27 km/h 0.0 mm High 37
8 Apr after 37.5 °C 34 % 28 km/h 0.0 mm High 37
9 Apr after 37.9 °C 29 % 30 km/h 0.0 mm Very high 39
10 Apr after 38.4 °C 28 % 28 km/h 0.0 mm Very high 39
11 Apr after 38.8 °C 28 % 28 km/h 0.0 mm Very high 39

Its twins: fires that started in the same weather

It started with an FWI of 34.2, a minimum humidity of 30% and 2 days without rain. Fires in the area that started in weather like this since 2016: 48.

FWI at the start 34.2
Minimum humidity 30 %
Days without rain 2
this fire chosen twins rest of the area
Almost identicalSimilar

Outlines of the closest twins

Chae Hom fire, March 2025
1,058 ha 7 days FWI 33.3 Min. humidity 31 % 30 km away, in 2025

First rain (1 mm or more) after it ended: none in the following ten days.

What happened to them

8 days
median duration
1,381 ha
median area
100 %
went past 1,000 ha
2.2 mm
rain at the end (median; 35 of 48 had it)

It burned an area similar to its twins (1,474 ha against a median of 1,381 ha) and lasted 9 days, against 8 days.

In 13 of 48, not even 1 mm fell in the ten days after the end: they went out without rain. In the rest, the first rainy day brought a median of 2.2 mm.

This is a bank of analogues: it shows what usually happens, not what will happen. With fewer than 15 twins we give no figures. How we calculate it

How it ended

—first rain
—no rain in ten days
38km/h · max. gust

It was considered over on 1 Apr, and not even 1 mm fell in the following ten days: it went out without rain. Twins with rain when they ended: 35 of 48, with a median of 2.2 mm.

Weather on this page: Open-Meteo.com (CC BY 4.0) · Copernicus Climate Change Service (ERA5)

How a twin is chosen

  • Same area: fires that have already ended, less than 250 km from this one, since 2016.
  • Same start: we compare the FWI on the first day, the minimum humidity that day and the run of days without rain before it. The slider sets how much they may differ.
  • Only pages with final weather data (ERA5 reanalysis) calculated in the same way as this fire’s; agricultural and grass burns and pages with data under review are left out.
  • Fires burning at the same time as this one (a week before or after) are left out: they share the same spell of weather and do not count as a precedent.
  • They are sorted by similarity, and the outlines of the first five are drawn.

How we calculate it

Before and after, from space

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

Before · 17 Mar 2023
After · 8 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 30 March 2023 the air beside the fire reached 100 µg/m³ of PM2.5. That day averaged 56: 3.7 times the WHO daily guideline (15).

PM2.5 peak100 µg/m³
Days over the guideline10 days
PM10143 µg/m³
Optical depth1.20
24 Mar26 Mar28 Mar30 Mar1 Apr
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 · 39Every 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 San Kamphaeng fire last?
According to the heat detections seen by satellite inside the perimeter, it burned from 24 March 2023 to 1 April 2023 (9 days). The perimeter dates it from 26 March 2023 to 30 March 2023.
How much area did it burn?
The perimeter GWIS (Copernicus) rebuilt from heat detections is 1,474 hectares (14.7 km²). It is an estimate: official national figures may differ.
Which municipalities burned?
The fire entered 2 municipalities: San Kamphaeng (1,048 ha, 4.4 %); Mae On (434 ha, 0.9 %).
What was the weather like?
During the fire the temperature reached 37.5 °C, humidity dropped to 21 % and gusts hit 38 km/h. The fire danger index (FWI) reached 44, 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.
How did the fires that started in similar weather in this area end?
Fires less than 250 km away that started since 2016 with a similar FWI, humidity and dry spell: 48. Their median duration was 8 days and their median area 1,381 ha; 100 % went past 1,000 ha. In 13 of 48, not even 1 mm fell in the ten days after the end: they went out without rain. In the rest, the first rainy day brought a median of 2.2 mm.

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 · 2 Changes in area, dates, name, official record or merged pages, compared every night since 24 October 2026.
  1. Last day with fire: 30 March 2023 → 1 April 2023.
  2. Start date: 26 March 2023 → 24 March 2023.

RSS Changes to this page With cross-checks and a citable version

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 adjusted with the VIIRS detections inside the perimeter, which said 26 March 2023 to 30 March 2023. 39 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.