Yoni fire, 29 March 2018 Yoni
The fire started on 29 March 2018 in Yoni, Sierra Leone, and satellites saw it burning for 17 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 4,358 hectares from heat detections, spread across a single municipality.
It is the 42th largest in Northern since 2016 (of 1112 with a page). Number 3 in Sierra Leone in 2018, of 104.
Compare with…
Suggestions: Yoni · 2017Yoni · 2016Yoni · 2017Yoni · 2026
- Burnt area
- 4,358ha
- GWIS perimeter (Copernicus)
- Duration
- 17days
- 29 Mar 2018 – 14 Apr 2018
- Municipalities hit
- 1
- chiefdoms
- Started on
- 29 Mar
- 2018
- Heat detections
- 155
- in a single hotspot: 426 MW
- Danger at start
- 0
- Very low · FWI index
- Average daily power
- 381MW
- 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 0 days without rain (1 mm or more) when it started. Rain came after the fire: 13.0 mm on 8 Apr.
This area had burned before
18% of the perimeter overlaps earlier fires recorded since 2016: 230 ha in 2016, 611 ha in 2017. Part of it burned more than once, so the yearly figures add up to more than the 781 ha that had burned before.
- 472 ha Yoni fire, March 2017 1,439 ha in total; the hectares shown are those it shares with this fire
- 230 ha Yoni fire, March 2016 1,473 ha in total; the hectares shown are those it shares with this fire
- 139 ha Yoni fire, April 2017 2,617 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
-
Yoni where it started4,386 ha reached on 29 Mar3.6 %
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.
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) |
|---|---|---|---|---|---|
| 3 Apr | 30.7 °C | 73 % | 27 km/h | 9.5 mm | Very low 0 |
| 4 Apr | 34.5 °C | 53 % | 28 km/h | 0.2 mm | Very low 2 |
| 5 Apr | 33.7 °C | 49 % | 30 km/h | 0.5 mm | Low 7 |
| 6 Apr | 34.2 °C | 51 % | 32 km/h | 0.0 mm | Low 10 |
| 7 Apr | 31.2 °C | 64 % | 30 km/h | 7.7 mm | Very low 0 |
| 8 Apr | 31.0 °C | 70 % | 26 km/h | 13.0 mm | Very low 0 |
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.
Detections table · 155Every satellite heat detection, one by one, with time, satellite, power and coordinates.
| Date and time | Satellite | FRP (MW) | Lat | Lon |
|---|
Other fires nearby
- 4,535 haYoni14 April 2026 · 20 days · 5 km away
- 4,665 haMasimera1 April 2017 · 17 days · 15 km away
- 4,208 haMasimera7 April 2026 · 26 days · 15 km away
- 3,669 haKoya29 March 2018 · 17 days · 18 km away
- 5,729 haMasimera13 April 2026 · 21 days · 21 km away
- 5,307 haMasimera5 April 2026 · 29 days · 22 km away
Frequently asked questions
- How long did the Yoni fire last?
- According to the heat detections seen by satellite inside the perimeter, it burned from 29 March 2018 to 14 April 2018 (17 days). The perimeter dates it from 3 April 2018 to 7 April 2018.
- How much area did it burn?
- The perimeter GWIS (Copernicus) rebuilt from heat detections is 4,358 hectares (43.6 km²). It is an estimate: official national figures may differ.
- Which municipalities burned?
- The fire only entered Yoni (4,386 ha, 3.6 %).
- What was the weather like?
- During the fire the temperature reached 34.5 °C, humidity dropped to 49 % and gusts hit 32 km/h. The fire danger index (FWI) reached 10, class Low.
- 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.
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 3 April 2018 to 7 April 2018. 155 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.
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.