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Nieni fire, 12 April 2024 Nieni, Kunike, Sambaya

Out · last detection 23 Apr 2024, 13:27 UTC

The fire started on 12 April 2024 in Nieni, Sierra Leone, and satellites saw it burning for 12 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 3,922 hectares from heat detections, spread across 3 municipalities.

It is the 56th largest in Northern since 2016 (of 1112 with a page). Number 2 in Sierra Leone in 2024, of 140.

Compare with…
Burnt area
3,922ha
GWIS perimeter (Copernicus)
Duration
12days
12 Apr 2024 – 23 Apr 2024
Municipalities hit
3
chiefdoms
Started on
12 Apr
2024
Heat detections
158
in a single hotspot: 247 MW
Danger at start
26
High · FWI index
Average daily power
604MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 12 Apr23 Apr
23 Apr 2024

How it evolved, day by day

14 Apr 2024 · 179 MW · 12 15 Apr 2024 · 571 MW · 30 16 Apr 2024 · 1,292 MW · 23 17 Apr 2024 · 18 MW · 2 18 Apr 2024 · 704 MW · 28 19 Apr 2024 · 32 MW · 6 20 Apr 2024 · 143 MW · 3 23 Apr 2024 · 1,890 MW · 36
14 Apr 16 Apr 18 Apr 20 Apr 23 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

38°high
40km/h · peak gust
26%lowest humidity

It had gone 0 days without rain (1 mm or more) when it started. Rain came after the fire: 2.7 mm on 28 Apr.

This area had burned before

68% of the perimeter overlaps earlier fires recorded since 2016: 1,200 ha in 2016, 1,339 ha in 2017, 370 ha in 2018, 818 ha in 2019, 822 ha in 2020, 92 ha in 2021, 1,651 ha in 2023. Part of it burned more than once, so the yearly figures add up to more than the 2,657 ha that had burned before.

How big is it?

10 km
It burned the equivalent of 2.5% of the area of London (39 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. Nieni where it started
    1,962 ha reached on 11 Apr
    0.9 %
  2. 1,771 ha reached on 11 Apr
    2.2 %
  3. 212 ha reached on 11 Apr
    0.3 %

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 area1.9 ha
Residents≈ 800

Inside the perimeter there were about 1.9 hectares of built-up land and about 800 residents (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)
12 Apr 37.3 °C 39 % 33 km/h 0.1 mm High 26
13 Apr 37.9 °C 38 % 29 km/h 0.0 mm High 27
14 Apr 37.4 °C 32 % 30 km/h 0.0 mm High 30
15 Apr 38.1 °C 26 % 31 km/h 0.0 mm High 35
16 Apr 38.0 °C 33 % 25 km/h 3.7 mm Moderate 15
17 Apr 36.3 °C 38 % 34 km/h 1.8 mm Moderate 17
18 Apr 36.6 °C 34 % 27 km/h 0.0 mm High 25
19 Apr 36.1 °C 39 % 38 km/h 0.0 mm High 30
20 Apr 33.7 °C 55 % 33 km/h 3.2 mm Low 6
21 Apr 31.3 °C 67 % 40 km/h 4.9 mm Very low 3
22 Apr 33.3 °C 53 % 23 km/h 0.7 mm Low 8
23 Apr 35.2 °C 43 % 21 km/h 0.0 mm Moderate 16
24 Apr after 36.7 °C 35 % 34 km/h 0.0 mm High 25
25 Apr after 35.9 °C 35 % 32 km/h 0.0 mm High 26
26 Apr after 36.1 °C 36 % 32 km/h 0.0 mm High 27
27 Apr after 37.8 °C 41 % 35 km/h 0.3 mm High 26
28 Apr after 35.6 °C 41 % 24 km/h 2.7 mm Low 11

Before and after, from space

Drag the line to compare the same ground before the fire and after it.

Before · 5 Apr 2024
After · 30 Apr 2024

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 22 April 2024 the air beside the fire reached 139 µg/m³ of PM2.5. That day averaged 72: 4.8 times the WHO daily guideline (15).

PM2.5 peak139 µg/m³
Days over the guideline17 days
PM10199 µg/m³
Optical depth1.88
1011121314151617181920212223242526
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 · 158Every 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 Sierra Leone ›

Frequently asked questions

How long did the Nieni fire last?
GWIS (Copernicus) dates it between 12 April 2024 and 23 April 2024: 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 3,922 hectares (39.2 km²). It is an estimate: official national figures may differ.
Which municipalities burned?
The fire entered 3 municipalities: Nieni (1,962 ha, 0.9 %); Kunike (1,771 ha, 2.2 %); Sambaya (212 ha, 0.3 %).
What was the weather like?
During the fire the temperature reached 38.1 °C, humidity dropped to 26 % and gusts hit 40 km/h. The fire danger index (FWI) reached 35, class High.
Where does this data come from?
From the GWIS (Copernicus) burnt perimeter, NASA FIRMS VIIRS hotspots and the administrative boundaries of Sierra Leone (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; 2 polygons grouped in this page.
  • Dates from the perimeter: the VIIRS detections inside it did not change them. 158 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 ADM3 (Creative Commons Attribution 4.0 (CC BY 4.0)). 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.