Siak fire, August 2018 Siak, Bengkalis
The fire started on 9 August 2018 in Siak, Indonesia, and satellites saw it burning for 12 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 2,728 hectares from heat detections, spread across 2 municipalities.
It is the 39th largest in Riau since 2016 (of 110 with a page). Number 40 in Indonesia in 2018, of 107.
Compare with…
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
- 2,728ha
- GWIS perimeter (Copernicus)
- Duration
- 12days
- 9 Aug 2018 – 20 Aug 2018
- Municipalities hit
- 2
- regencies
- Started on
- 9 Aug
- 2018
- Danger at start
- 1
- Very low · FWI index
Where it burned
The weather it burned in
It had gone 0 days without rain (1 mm or more) when it started. Rain came after the fire: 1.7 mm on 21 Aug.
This area had burned before
19% of the perimeter overlaps earlier fires recorded since 2016: 543 ha in 2016, 58 ha in 2017. Part of it burned more than once, so the yearly figures add up to more than the 520 ha that had burned before.
How big is it?
London boundary: geoBoundaries · Office for National Statistics (Open Government Licence v3.0).
Jakarta boundary: geoBoundaries · Badan Pusat Statistik (BPS - Statistics Indonesia), World Food Programme, OCHA ROAP (CC BY 3.0 IGO).
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
-
Siak where it started2,688 ha0.3 %
-
59 ha0.0 %
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 2020Inside the perimeter there was no noticeable built-up land and almost nobody lived there (GHSL 2020, 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.
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) |
|---|---|---|---|---|---|
| 9 Aug | 32.2 °C | 59 % | 20 km/h | 0.0 mm | Very low 1 |
| 10 Aug | 33.4 °C | 55 % | 26 km/h | 0.0 mm | Very low 4 |
| 11 Aug | 34.6 °C | 47 % | 27 km/h | 0.1 mm | Low 6 |
| 12 Aug | 34.0 °C | 51 % | 27 km/h | 0.2 mm | Low 8 |
| 13 Aug | 35.1 °C | 46 % | 30 km/h | 0.0 mm | Low 9 |
| 14 Aug | 34.6 °C | 51 % | 37 km/h | 0.2 mm | Low 11 |
| 15 Aug | 34.4 °C | 53 % | 37 km/h | 0.0 mm | Moderate 12 |
| 16 Aug | 35.2 °C | 51 % | 24 km/h | 2.8 mm | Very low 3 |
| 17 Aug | 33.0 °C | 59 % | 32 km/h | 1.0 mm | Very low 4 |
| 18 Aug | 34.5 °C | 49 % | 23 km/h | 1.4 mm | Low 6 |
| 19 Aug | 34.5 °C | 49 % | 32 km/h | 0.0 mm | Low 11 |
| 20 Aug | 34.1 °C | 54 % | 33 km/h | 6.7 mm | Very low 1 |
| 21 Aug after | 33.2 °C | 62 % | 24 km/h | 1.7 mm | Very low 2 |
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.
Other fires nearby
Frequently asked questions
- How long did the Siak fire last?
- GWIS (Copernicus) dates it between 9 August 2018 and 20 August 2018: 12 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 2,728 hectares (27.3 km²). It is an estimate: official national figures may differ.
- Which municipalities burned?
- The fire entered 2 municipalities: Siak (2,688 ha, 0.3 %); Bengkalis (59 ha, 0.0 %).
- What was the weather like?
- During the fire the temperature reached 35.2 °C, humidity dropped to 46 % and gusts hit 37 km/h. The fire danger index (FWI) reached 12, class Moderate.
- 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.
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.
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. 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 2020, 100 m cells), summed inside the perimeter: an estimate of what was there, not a damage count.
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.