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Derre fire, 12 September 2025 Derre, Morrumbala

Out · last detection 23 Sept 2025, 11:27 UTC

The fire started on 12 September 2025 in Derre, Mozambique, and satellites saw it burning for 11 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 5,111 hectares from heat detections, spread across 2 municipalities.

It is the 351th largest in Zambézia since 2016 (of 842 with a page). Number 126 in Mozambique in 2025, of 313.

Burnt area
5,111ha
GWIS perimeter (Copernicus)
Duration
11days
12 Sept 2025 – 22 Sept 2025
Municipalities hit
2
districts
Started on
12 Sept
2025
Heat detections
181
in a single hotspot: 104 MW
Danger at start
42
Very high · FWI index
Energy released
1.2GW
sum of detected power

Where it burned

23 Sept 2025
HOTSPOTS BY DAY 12 Sept22 Sept

How it evolved, day by day

121314161718192223

Fire radiative power detected each day, in megawatts, and number of hotspots. The magenta bar marks the peak day.

The weather it burned in

37°high
47km/h · peak gust
21%lowest humidity

It had gone 24 days without rain (1 mm or more) when it started. Rain came after the fire: 1.0 mm on 26 Sept.

This area had burned before

74% of the perimeter overlaps earlier fires recorded since 2016: 421 ha in 2016, 202 ha in 2018, 846 ha in 2019, 19 ha in 2020, 172 ha in 2021, 392 ha in 2022, 1,872 ha in 2023, 894 ha in 2024. Part of it burned more than once, so the yearly figures add up to more than the 3,760 ha that had burned before.

What happened to each town

  1. Derre where it started
    3,713 ha reached on 7 Sept
    0.8 %
  2. 1,423 ha reached on 13 Sept
    0.2 %

Burnt area inside each municipality, from crossing the GWIS perimeter with administrative boundaries. The distance is from the town centre 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)
12 Sept 33.7 °C 24 % 36 km/h 0.0 mm Very high 42
13 Sept 31.3 °C 32 % 33 km/h 0.0 mm Very high 39
14 Sept 32.8 °C 25 % 32 km/h 0.0 mm Very high 40
15 Sept 32.0 °C 31 % 32 km/h 0.0 mm Very high 40
16 Sept 34.4 °C 25 % 24 km/h 0.0 mm High 37
17 Sept 36.7 °C 21 % 31 km/h 0.0 mm Very high 42
18 Sept 36.3 °C 24 % 45 km/h 0.0 mm Extreme 52
19 Sept 32.8 °C 36 % 47 km/h 0.0 mm Very high 46
20 Sept 30.5 °C 34 % 42 km/h 0.2 mm Very high 40
21 Sept 30.9 °C 34 % 39 km/h 0.1 mm Very high 41
22 Sept 33.0 °C 33 % 31 km/h 0.0 mm Very high 38
23 Sept after 37.0 °C 22 % 40 km/h 0.0 mm Very high 50
24 Sept after 35.6 °C 27 % 37 km/h 0.0 mm Very high 49
25 Sept after 34.1 °C 29 % 46 km/h 0.0 mm Extreme 54
26 Sept after 29.1 °C 50 % 40 km/h 1.0 mm High 23

Before and after, from space

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

Before · 5 Sept 2025
After · 29 Sept 2025

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 September 2025 the air beside the fire reached 169 µg/m³ of PM2.5. That day averaged 62: 4.2 times the WHO daily guideline (15).

PM2.5 peak169 µg/m³
Days over the guideline13 days
PM10173 µg/m³
Optical depth1.40
10111213141516171819202122232425
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 · 181Every 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 Mozambique ›

Frequently asked questions

How long did the Derre fire last?
GWIS (Copernicus) dates it between 12 September 2025 and 22 September 2025: 11 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 5,111 hectares (51.1 km²). It is an estimate: official national figures may differ.
Which municipalities burned?
The fire entered 2 municipalities: Derre (3,713 ha, 0.8 %); Morrumbala (1,423 ha, 0.2 %).
What was the weather like?
During the fire the temperature reached 36.7 °C, humidity dropped to 21 % and gusts hit 47 km/h. The fire danger index (FWI) reached 52, class Extreme.
Where does this data come from?
From the GWIS (Copernicus) burnt perimeter, NASA FIRMS VIIRS hotspots and the administrative boundaries of Mozambique (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

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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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.