Ulang fire, 23 March 2023 Ulang
The fire started on 23 March 2023 in Ulang, South Sudan, and satellites saw it burning for 20 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 5,101 hectares from heat detections, spread across a single municipality.
It is the 281th largest in Upper Nile since 2016 (of 285 with a page). Number 105 in South Sudan in 2023, of 106.
Compare with…
Suggestions: Akobo · 2022Ulang · 2016Ulang · 2017Nyirol · 2024
- Burnt area
- 5,101ha
- GWIS perimeter (Copernicus)
- Duration
- 20days
- 23 Mar 2023 – 11 Apr 2023
- Municipalities hit
- 1
- counties
- Started on
- 23 Mar
- 2023
- Heat detections
- 164
- in a single hotspot: 229 MW
- Danger at start
- 57
- Extreme · FWI index
- Average daily power
- 166MW
- detected power per day, on average
Where it burned
How it evolved, day by day
Fire radiative power detected each day, in megawatts, and number of hotspots. The magenta bar marks the peak day.
The weather it burned in
It had gone more than two months without rain (1 mm or more) when it started. Rain came after the fire: 1.4 mm on 12 Apr.
This area had burned before
99% of the perimeter overlaps earlier fires recorded since 2016: 979 ha in 2016, 2,426 ha in 2017, 4,860 ha in 2018, 13 ha in 2019, 4,940 ha in 2022. Part of it burned more than once, so the yearly figures add up to more than the 5,075 ha that had burned before.
- 3,400 ha Akobo fire, January 2022 63,860 ha in total; the hectares shown are those it shares with this fire
- 2,426 ha Ulang fire, December 2016 129,779 ha in total; the hectares shown are those it shares with this fire
- 2,369 ha Ulang fire, December 2017 35,904 ha in total; the hectares shown are those it shares with this fire
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
-
Ulang where it started5,132 ha reached on 23 Mar1.1 %
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 2025Inside 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) |
|---|---|---|---|---|---|
| 25 Mar | 40.0 °C | 19 % | 36 km/h | 0.0 mm | Extreme 57 |
| 26 Mar | 37.0 °C | 26 % | 43 km/h | 0.9 mm | Very high 45 |
| 27 Mar | 36.7 °C | 26 % | 34 km/h | 0.0 mm | Very high 43 |
| 28 Mar | 38.3 °C | 11 % | 34 km/h | 0.0 mm | Extreme 56 |
| 29 Mar | 39.3 °C | 13 % | 26 km/h | 0.0 mm | Extreme 52 |
| 30 Mar | 39.3 °C | 18 % | 28 km/h | 0.0 mm | Extreme 51 |
| 31 Mar | 39.9 °C | 5 % | 34 km/h | 0.0 mm | Extreme 68 |
| 1 Apr | 37.3 °C | 21 % | 24 km/h | 0.0 mm | Very high 50 |
| 2 Apr | 39.6 °C | 11 % | 24 km/h | 0.0 mm | Very high 49 |
| 3 Apr | 40.7 °C | 8 % | 36 km/h | 0.0 mm | Extreme 62 |
| 4 Apr | 39.6 °C | 17 % | 36 km/h | 0.0 mm | Extreme 59 |
| 5 Apr | 39.6 °C | 17 % | 35 km/h | 0.0 mm | Extreme 59 |
| 6 Apr | 40.1 °C | 19 % | 44 km/h | 0.0 mm | Extreme 65 |
| 7 Apr | 38.4 °C | 23 % | 33 km/h | 0.0 mm | Very high 49 |
| 8 Apr | 39.7 °C | 22 % | 47 km/h | 0.0 mm | Extreme 63 |
| 9 Apr | 39.9 °C | 19 % | 43 km/h | 0.0 mm | Extreme 58 |
| 10 Apr | 39.9 °C | 21 % | 44 km/h | 0.0 mm | Extreme 61 |
| 11 Apr | 40.3 °C | 19 % | 51 km/h | 0.0 mm | Extreme 67 |
| 12 Apr after | 39.5 °C | 25 % | 49 km/h | 1.4 mm | Extreme 50 |
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.
The smoke
CAMS · CopernicusOn 31 March 2023 the air beside the fire reached 130 µg/m³ of PM2.5. That day averaged 48: 3.2 times the WHO daily guideline (15).
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 · 164Every satellite heat detection, one by one, with time, satellite, power and coordinates.
| Date and time | Satellite | FRP (MW) | Lat | Lon |
|---|
Other fires nearby
- 63,860 haAkobo24 January 2022 · 37 days · 11 km away
- 77,472 haNyirol4 January 2024 · 28 days · 20 km away
- 83,713 haUlang6 March 2022 · 30 days · 24 km away
- 58,283 haUlangJanuary 2019 · 26 days · 24 km away
- 129,779 haUlangDecember 2016 · 49 days · 26 km away
- 35,904 haUlangDecember 2017 · 24 days · 27 km away
Frequently asked questions
- How long did the Ulang fire last?
- According to the heat detections seen by satellite inside the perimeter, it burned from 23 March 2023 to 11 April 2023 (20 days). The perimeter dates it from 25 March 2023 to 8 April 2023.
- How much area did it burn?
- The perimeter GWIS (Copernicus) rebuilt from heat detections is 5,101 hectares (51.0 km²). It is an estimate: official national figures may differ.
- Which municipalities burned?
- The fire only entered Ulang (5,132 ha, 1.1 %).
- What was the weather like?
- During the fire the temperature reached 40.7 °C, humidity dropped to 5 % and gusts hit 47 km/h. The fire danger index (FWI) reached 68, class Extreme.
- Where does this data come from?
- From the GWIS (Copernicus) burnt perimeter, NASA FIRMS VIIRS hotspots and the administrative boundaries of South Sudan (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.
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.
- Last day with fire: 8 April 2023 → 11 April 2023.
- Start date: 25 March 2023 → 23 March 2023.
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 adjusted with the VIIRS detections inside the perimeter, which said 25 March 2023 to 8 April 2023. 164 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.
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.