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ID · Indonesia · –

Kapuas fire, 23 September 2023 Kapuas

Out · last measured on 30 Sept 2023

The fire started on 23 September 2023 in Kapuas, Indonesia, and satellites saw it burning for 8 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 1,660 hectares from heat detections, spread across a single municipality.

It is the 136th largest in Central Kalimantan since 2016 (of 154 with a page). Number 121 in Indonesia in 2023, of 162.

Compare with…

Suggestions: Pulang Pisau · 2019Barito Selatan · 2018Kapuas · 2019Kapuas · 2026

We have the GWIS perimeter for this fire, but the VIIRS sensors did not capture it in enough detail: no day-by-day evolution, but the split by municipality is there.

Burnt area
1,660ha
GWIS perimeter (Copernicus)
Duration
8days
23 Sept 2023 – 30 Sept 2023
Municipalities hit
1
regencies
Started on
23 Sept
2023
Danger at start
13
Moderate · FWI index

Where it burned

The weather it burned in

38°high
32km/h · peak gust
31%lowest humidity

It had gone 3 days without rain (1 mm or more) when it started. Rain came after the fire: 6.9 mm on 9 Oct.

This area had burned before

91% of the perimeter overlaps earlier fires recorded since 2016: 2,435 ha in 2019. Part of it burned more than once, so the yearly figures add up to more than the 1,514 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. Kapuas where it started
    1,672 ha
    0.1 %

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)
23 Sept 35.0 °C 39 % 24 km/h 0.0 mm Moderate 13
24 Sept 36.5 °C 40 % 25 km/h 0.0 mm Moderate 13
25 Sept 36.3 °C 36 % 29 km/h 0.0 mm Moderate 16
26 Sept 36.3 °C 34 % 32 km/h 0.0 mm Moderate 17
27 Sept 37.1 °C 31 % 29 km/h 0.0 mm Moderate 21
28 Sept 38.1 °C 31 % 25 km/h 0.0 mm Moderate 21
29 Sept 37.8 °C 32 % 22 km/h 0.0 mm Moderate 21
30 Sept 36.8 °C 33 % 28 km/h 0.0 mm High 24
1 Oct after 36.1 °C 29 % 28 km/h 0.0 mm High 24
2 Oct after 36.5 °C 28 % 30 km/h 0.0 mm High 26
3 Oct after 36.5 °C 38 % 25 km/h 0.0 mm High 25
4 Oct after 36.4 °C 42 % 21 km/h 0.1 mm High 22
5 Oct after 36.6 °C 44 % 21 km/h 0.1 mm High 22
6 Oct after 36.6 °C 41 % 26 km/h 0.2 mm High 23
7 Oct after 38.0 °C 34 % 28 km/h 0.0 mm High 24
8 Oct after 38.2 °C 35 % 28 km/h 0.8 mm High 24
9 Oct after 35.2 °C 48 % 26 km/h 6.9 mm Very low 3

Its twins: fires that started in the same weather

It started with an FWI of 12.6, a minimum humidity of 39% and 3 days without rain. Fires in the area that started in weather like this since 2017: 24.

FWI at the start 12.6
Minimum humidity 39 %
Days without rain 3
this fire chosen twins rest of the area
Almost identicalSimilar

Outlines of the closest twins

Pulang Pisau fire, September 2019
4,779 ha 24 days FWI 14.9 Min. humidity 39 % 29 km away, in 2019

First rain (1 mm or more) after it ended: 3.1 mm on 26 Sept.

See its page Compare with this fire

What happened to them

19 days
median duration
2,732 ha
median area
100 %
went past 1,000 ha
3.5 mm
rain at the end (median; 24 of 24 had it)

It stayed below its twins: 1,660 ha against a median of 2,732 ha. It lasted 8 days, against 19 days.

All of them had rain in the ten days after the end: the first rainy day brought a median of 3.5 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

6.9 mmfirst rain
9 Oct9 days after it ended
32km/h · max. gust

It was considered over on 30 Sept, and on 9 Oct 6.9 mm fell. We do not know whether the rain or the firefighters put it out. Twins with rain when they ended: 24 of 24, with a median of 3.5 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 2017.
  • 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 · 16 Sept 2023
After · 7 Oct 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 29 September 2023 the air beside the fire reached 600 µg/m³ of PM2.5. That day averaged 208: 14 times the WHO daily guideline (15).

PM2.5 peak600 µg/m³
Days over the guideline13 days
PM10857 µg/m³
Optical depth6.19
21 Sept24 Sept27 Sept30 Sept3 Oct
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)

Other fires nearby

All fires in Indonesia

Frequently asked questions

How long did the Kapuas fire last?
GWIS (Copernicus) dates it between 23 September 2023 and 30 September 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 1,660 hectares (16.6 km²). It is an estimate: official national figures may differ.
Which municipalities burned?
The fire only entered Kapuas (1,672 ha, 0.1 %).
What was the weather like?
During the fire the temperature reached 38.1 °C, humidity dropped to 31 % and gusts hit 32 km/h. The fire danger index (FWI) reached 24, class High.
Where does this data come from?
From the GWIS (Copernicus) burnt perimeter, NASA FIRMS VIIRS hotspots and the administrative boundaries of Indonesia (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 2017 with a similar FWI, humidity and dry spell: 24. Their median duration was 19 days and their median area 2,732 ha; 100 % went past 1,000 ha. All of them had rain in the ten days after the end: the first rainy day brought a median of 3.5 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: 112 · 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 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 112.

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. No 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.