Burned area
satellite only9,182ha
Perimeter published by GWIS (Copernicus).
- Source
- GWIS (Copernicus)
- Date
- 5 Sept 2018 – 5 Sept 2018
+− cross-check
No official record is matched to this page to compare it with.
ZA · South Africa ·
Nketoana fire, September 2018 Nketoana, Mafube
Out · last detection 5 Sept 2018, 23:59 UTC
The fire started on 5 September 2018 in Nketoana, South Africa, and satellites saw it burning for 1 day. Copernicus’s global GWIS system rebuilt a burnt perimeter of 9,182 hectares from heat detections, spread across 2 municipalities.
It is the 5th largest in Free State since 2016 (of 84 with a page). Number 6 in South Africa in 2018, of 96.
Use this data
Compare with…
Use this data
Fire page data · version 2026-10-24matches the official recordwith caveatssatellite onlymodel
When copying, the sentence is
Tick the figures you want: they make up the lede and the CSV.
Duration by satellite
satellite only1day
5 Sept 2018 to 5 Sept 2018: first and last day with fire on the page.
- Source
- GWIS (Copernicus) · NASA FIRMS · VIIRS
- Date
- last detection: 5 Sept 2018, 23:59 UTC
+− cross-check
Satellites pass a few times a day and cloud or smoke can hide the fire: a lack of detections is not an official extinction. Each country’s emergency service declares a fire contained or out.
Start
satellite only5 Sept 2018
First day with fire seen by the satellites or the perimeter.
- Source
- GWIS (Copernicus) · NASA FIRMS · VIIRS
- Date
- 5 Sept 2018
+− cross-check
No official record is matched to this page, so the alert time and the cause are not known here.
Hotspots
satellite only340
VIIRS detections at 375 m. Most intense hotspot: 195 MW.
- Source
- NASA FIRMS · VIIRS (Suomi NPP)
- Date
- 5 Sept 2018 – 5 Sept 2018
+− cross-check
There is no official record to compare with. Each hotspot is a pixel detected in one satellite pass, not a separate fire.
The worst day
satellite only11,673MW
Total radiative power on 5 September 2018; hotspots that day: 340.
- Source
- NASA FIRMS · VIIRS (FRP)
- Date
- 5 Sept 2018
+− cross-check
Fire radiative power (FRP) measures the energy the fire gives off when the satellite passes. Added up by day, it compares intensity, not area.
Danger at the start
model53.4FWI · extreme
Fire Weather Index (Canadian system) computed by WorldFires for the day the fire started. Consecutive days without rain before: 17.
- Source
- WorldFires calculation (Canadian FWI system)
- Date
- 5 Sept 2018, local noon
- Model
- ERA5 0,25° (ECMWF · Copernicus C3S) · Open-Meteo.com
+− cross-check
This is an index computed from weather model data, not a measurement of the fire nor an official warning. Danger warnings are issued by each country’s authority. Emergency number and official warnings
Weather during the fire
model29.1°C · 9% RH
High of 29.1 °C and minimum humidity of 9% on 5 September 2018; gusts of 52 km/h on 5 September 2018.
- Source
- weather model at the fire’s grid cell
- Date
- 5 Sept 2018 – 5 Sept 2018
- Model
- ERA5 0,25° (ECMWF · Copernicus C3S) · Open-Meteo.com
+− cross-check
These are model values for a cell of about 25 km, not from a weather station: they may differ from what was measured on the ground.
Living inside
model≈ 70people
Estimated residents inside the perimeter and 3.4 ha of built-up area (100 m grid, epoch 2020).
- Source
- GHSL R2023A · JRC
- Date
- calculated on 24 October 2026
+− cross-check
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.
This page’s change log has been kept since 24 October 2026: every night what it publishes is compared and the difference is logged. Anything earlier is reconstructed from each source’s date and marked as reconstructed.
Show
-
· reconstructed GHSLPopulation and built-up area computed
-
· reconstructed weatherWeather and FWI computed from the ERA5 reanalysis
What was saved on 24 October 2026
Every night a snapshot of what the page shows is saved. If anything changes, it appears in the list as a log entry.
- Area
- 9,182 ha
- Dates
- 5 Sept 2018 – 5 Sept 2018
- Name
- Nketoana
- Official record
- —
Versioned permanent link
https://worldfires.org/en/fire/nketoana-2018-09?v=2026-10-24A version keeps the area, dates, name and official record; the area as it was logged (changes under 2% are not logged). The map, hotspots and weather always show today’s data.
Citation
A lede of about 60 words figures only, no adjectives
CSV for this fire nketoana-2018-09.csv · daily, no individual hotspots
| fecha | focos_viirs | frp_mw | tmax_c | tmin_c | hr_min_pct | viento_max_kmh | racha_max_kmh | precip_mm | fwi | clase_fwi | dentro_del_incendio |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 2018-09-05 | 340 | 11,673 | 29.1 | 6.8 | 9 | 25.1 | 51.8 | 0 | 53.4 | extremo | 1 |
| 2018-09-06 | 0 | 0 | 28 | 14.6 | 14 | 33.3 | 68 | 0 | 65.2 | extremo | 0 |
| 2018-09-07 | 0 | 0 | 20 | 8.4 | 38 | 27.3 | 54.7 | 1.9 | 16 | moderado | 0 |
It is generated in your browser from this page’s data: one file per fire, aggregated by day and without individual hotspots.
Live widget for your story
It updates itself while the fire is still active and links to this page. Free, with the attribution shown at the bottom.
Sources for this page: GWIS (Copernicus), NASA FIRMS (VIIRS), ERA5 (ECMWF/Copernicus C3S) · Open-Meteo.com (CC BY 4.0), GHSL (JRC). Open-Meteo.com · How we build fire pages: methodology
- Burnt area
- 9,182ha
- GWIS perimeter (Copernicus)
- Duration
- 1day
- 5 Sept 2018 – 5 Sept 2018
- Municipalities hit
- 2
- municipalities
- Started on
- 5 Sept
- 2018
- Heat detections
- 340
- in a single hotspot: 195 MW
- Danger at start
- 53
- Extreme · FWI index
- Average daily power
- 11.7GW
- detected power per day, on average
Where it burned
HOTSPOTS BY DAY
5 Sept5 Sept
How it evolved, day by day
5 Sept 2018 · 11,673 MW · 340
Fire radiative power detected each day, in megawatts, and number of hotspots. The magenta bar marks the peak day.
The weather it burned in
29°high
52km/h · peak gust
9%lowest humidity
It had gone 17 days without rain (1 mm or more) when it started. Rain came after the fire: 1.9 mm on 7 Sept.
This area had burned before
0% of the perimeter overlaps earlier fires recorded since 2016: 16 ha in 2017.
How big is it?
London boundary: geoBoundaries · Office for National Statistics (Open Government Licence v3.0).
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).
Berlin boundary: geoBoundaries · Federal Agency for Cartography and Geodesy (dl-de/by-2-0).
This compares size, not location: both shapes are at the same scale, north up, centred on each other.
What happened to each town
-
Nketoana where it started8,345 ha reached on 5 Sept1.5 %
-
853 ha reached on 5 Sept0.2 %
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 2020Built-up area3.4 ha
Residents≈ 70
Inside the perimeter there were about 3.4 hectares of built-up land and about 70 residents (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)
Started with Strong wind: 30 % of the area in South Africa Very dry air: 37 % of the area in South Africa
| Day | High | Min. humidity | Peak gust | Rain | Danger (FWI) |
|---|---|---|---|---|---|
| 5 Sept | 29.1 °C | 9 % | 52 km/h | 0.0 mm | Extreme 53 |
| 6 Sept after | 28.0 °C | 14 % | 68 km/h | 0.0 mm | Extreme 65 |
| 7 Sept after | 20.0 °C | 38 % | 55 km/h | 1.9 mm | Moderate 16 |
Its twins: fires that started in the same weather
It started with an FWI of 53.4, a minimum humidity of 9% and 17 days without rain. Fires in the area that started in weather like this since 2016: 26.
FWI at the start
53.4
Minimum humidity
9 %
Days without rain
17
this fire
chosen twins
rest of the area
Almost identicalSimilar
Outlines of the closest twins
This fire · Nketoana fire, September 2018
9,182 ha
1 day
FWI 53.4
Min. humidity 9 %
Maluti a Phofung fire, October 2019
2,317 ha
5 days
FWI 53.0
Min. humidity 10 %
117 km away, in 2019
First rain (1 mm or more) after it ended: 1.7 mm on 25 Oct.
Maluti a Phofung fire, August 2024
3,386 ha
2 days
FWI 53.0
Min. humidity 7 %
97 km away, in 2024
First rain (1 mm or more) after it ended: none in the following ten days.
Midvaal fire, September 2021
2,788 ha
3 days
FWI 57.3
Min. humidity 7 %
119 km away, in 2021
First rain (1 mm or more) after it ended: 2.1 mm on 29 Sept.
Dr Pixley Ka Isaka Seme fire, August 2018
2,281 ha
1 day
FWI 54.1
Min. humidity 13 %
129 km away, in 2018
First rain (1 mm or more) after it ended: 2.4 mm on 8 Aug.
Ventersdorp/Tlokwe fire, September 2019
3,103 ha
1 day
FWI 52.1
Min. humidity 13 %
182 km away, in 2019
First rain (1 mm or more) after it ended: none in the following ten days.
What happened to them
- 2 days
- median duration
- 2,880 ha
- median area
- 100 %
- went past 1,000 ha
- 2.8 mm
- rain at the end (median; 16 of 26 had it)
It was 3.2 times larger than the median of its twins and lasted 1 day, against 2 days.
None of its 26 twins burned more. The weather on the first day does not explain everything: the wind in the following days, the fuel and the firefighting also count. In 10 of 26, 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 2.8 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
1.9 mmfirst rain
7 Sept2 days after it ended
52km/h · max. gust
It was considered over on 5 Sept, and on 7 Sept 1.9 mm fell. We do not know whether the rain or the firefighters put it out. Twins with rain when they ended: 16 of 26, with a median of 2.8 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.
Before and after, from space
Drag the line to compare the same ground before the fire and after it.
↔
Before · 29 Aug 2018
After · 12 Sept 2018
Sentinel-2 did not pass over on that day. Try another date, or use false colour, which is daily.
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 · 340Every 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 time | Satellite | FRP (MW) | Lat | Lon |
|---|
Other fires nearby
Frequently asked questions
- How long did the Nketoana fire last?
- GWIS (Copernicus) dates it between 5 September 2018 and 5 September 2018: 1 day 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 9,182 hectares (91.8 km²). It is an estimate: official national figures may differ.
- Which municipalities burned?
- The fire entered 2 municipalities: Nketoana (8,345 ha, 1.5 %); Mafube (853 ha, 0.2 %).
- What was the weather like?
- During the fire the temperature reached 29.1 °C, humidity dropped to 9 % and gusts hit 52 km/h. The fire danger index (FWI) reached 53, class Extreme.
- Where does this data come from?
- From the GWIS (Copernicus) burnt perimeter, NASA FIRMS VIIRS hotspots and the administrative boundaries of South Africa (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: 26. Their median duration was 2 days and their median area 2,880 ha; 100 % went past 1,000 ha. None of its 26 twins burned more. The weather on the first day does not explain everything: the wind in the following days, the fuel and the firefighting also count. In 10 of 26, 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 2.8 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: 10177 · 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
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. 340 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 ADM3 (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.