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Ulang fire, 21 March 2023 Ulang

Out · last detection 11 Apr 2023, 11:33 UTC

The fire started on 21 March 2023 in Ulang, South Sudan, and satellites saw it burning for 22 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 5,662 hectares from heat detections, spread across a single municipality.

It is the 218th largest in Upper Nile since 2016 (of 284 with a page). Number 85 in South Sudan in 2023, of 106.

Compare with…

Suggestions: Akobo · 2022Ulang · 2016Ulang · 2022Nyirol · 2022

Burnt area
5,662ha
GWIS perimeter (Copernicus)
Duration
22days
21 Mar 2023 – 11 Apr 2023
Municipalities hit
1
counties
Started on
21 Mar
2023
Heat detections
302
in a single hotspot: 127 MW
Danger at start
51
Extreme · FWI index
Average daily power
258MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 21 Mar11 Apr
11 Apr 2023

How it evolved, day by day

21 Mar 2023 · 3 MW · 1 24 Mar 2023 · 127 MW · 13 25 Mar 2023 · 399 MW · 39 27 Mar 2023 · 82 MW · 8 28 Mar 2023 · 393 MW · 17 29 Mar 2023 · 118 MW · 12 30 Mar 2023 · 82 MW · 12 31 Mar 2023 · 198 MW · 5 2 Apr 2023 · 200 MW · 9 3 Apr 2023 · 2,420 MW · 76 4 Apr 2023 · 20 MW · 2 5 Apr 2023 · 14 MW · 2 6 Apr 2023 · 19 MW · 2 7 Apr 2023 · 176 MW · 6 8 Apr 2023 · 57 MW · 9 9 Apr 2023 · 133 MW · 16 10 Apr 2023 · 15 MW · 3 11 Apr 2023 · 184 MW · 12
21 Mar 27 Mar 30 Mar 3 Apr 6 Apr 9 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

41°high
51km/h · peak gust
5%lowest humidity

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

94% of the perimeter overlaps earlier fires recorded since 2016: 782 ha in 2016, 1,449 ha in 2017, 1,242 ha in 2018, 617 ha in 2019, 405 ha in 2021, 6,253 ha in 2022. Part of it burned more than once, so the yearly figures add up to more than the 5,323 ha that had burned before.

How big is it?

10 km
It burned the equivalent of 3.6% of the area of London (57 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. Ulang where it started
    5,698 ha reached on 16 Mar
    1.2 %

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 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)
21 Mar 38.1 °C 17 % 28 km/h 0.0 mm Extreme 51
22 Mar 39.7 °C 5 % 32 km/h 0.0 mm Extreme 60
23 Mar 40.1 °C 6 % 34 km/h 0.0 mm Extreme 69
24 Mar 39.3 °C 16 % 32 km/h 0.0 mm Extreme 61
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 69
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.

Before · 14 Mar 2023
After · 18 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 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).

PM2.5 peak130 µg/m³
Days over the guideline26 days
PM10187 µg/m³
Optical depth1.56
192021222324252627282930311234567891011121314
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 · 302Every 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 South Sudan ›

Frequently asked questions

How long did the Ulang fire last?
GWIS (Copernicus) dates it between 21 March 2023 and 11 April 2023: 22 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 5,662 hectares (56.6 km²). It is an estimate: official national figures may differ.
Which municipalities burned?
The fire only entered Ulang (5,698 ha, 1.2 %).
What was the weather like?
During the fire the temperature reached 40.7 °C, humidity dropped to 5 % and gusts hit 51 km/h. The fire danger index (FWI) reached 69, 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 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

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.

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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. 302 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.