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DZ · Algeria · –

El Marsa fire, August 2020 المرسى · El Marsa

Out · last detection 12 Aug 2020, 13:46 UTC

The fire started on 10 August 2020 in El Marsa, Algeria, and satellites saw it burning for 3 days. Copernicus mapped a burnt perimeter of 2,153 hectares from satellite imagery, spread across a single municipality.

It is the largest fire in Chlef since 2016 (of 14 with a page). Number 5 in Algeria in 2020, of 236.

The power measured by the satellite is low (26.1 MW in the strongest hotspot), more typical of grass or stubble burning, or a slow surface fire, than of a large crown fire.

Compare with…

Suggestions: Zeboudja · 2019Tadjena · 2021Talassa · 2020Abou El Hassen · 2020

Burnt area
2,153ha
Copernicus perimeter
Duration
3days
10 Aug 2020 – 12 Aug 2020
Municipalities hit
1
communes
Started on
10 Aug
2020
Heat detections
13
in a single hotspot: 26 MW
Danger at start
46
Very high · FWI index
Average daily power
50MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 10 Aug12 Aug
12 Aug 2020

How it evolved, day by day

11 Aug 2020 · 95 MW · 12 12 Aug 2020 · 4 MW · 1
11 Aug 12 Aug

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
45km/h · peak gust
19%lowest humidity

It had gone more than two months without rain (1 mm or more) when it started.

This area had burned before

No earlier perimeters overlap this fire since 2016, when the satellite record begins.

How big is it?

10 km
It burned the equivalent of 1.4% of the area of London (22 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. El Marsa المرسى 10,807 inhabitants · 1.3 km from the centre where it started
    2,158 ha reached on 11 Aug
    18 %

Burnt area inside each municipality, from crossing the official 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.

What burned

  • Mixed forest85 %
  • Other natural land11 %
  • Broadleaved forest2.9 %

Land cover inside the perimeter as reported by Copernicus EFFIS (outside the Corine Land Cover area).

People and buildings inside the perimeter

GHSL 2020
Built-up area0.29 ha
Residents≈ 20

Inside the perimeter there were about 0.29 hectares of built-up land and about 20 residents (GHSL 2020, 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.

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)

Started with 60 days without rain: 16 % of the area in Algeria

Day High Min. humidity Peak gust Rain Danger (FWI)
10 Aug 37.7 °C 19 % 39 km/h 0.0 mm Very high 46
11 Aug 36.1 °C 29 % 32 km/h 0.0 mm High 33
12 Aug 32.6 °C 40 % 45 km/h 0.0 mm Very high 39
13 Aug after 32.3 °C 50 % 30 km/h 0.0 mm High 23
14 Aug after 34.3 °C 47 % 32 km/h 0.0 mm High 24
15 Aug after 32.2 °C 48 % 33 km/h 0.0 mm High 30
16 Aug after 31.2 °C 34 % 39 km/h 0.0 mm Very high 44
17 Aug after 30.9 °C 34 % 35 km/h 0.0 mm Very high 42
18 Aug after 32.3 °C 32 % 28 km/h 0.0 mm High 34
19 Aug after 35.8 °C 34 % 27 km/h 0.0 mm High 34
20 Aug after 34.1 °C 48 % 22 km/h 0.0 mm High 31
21 Aug after 33.1 °C 50 % 29 km/h 0.0 mm High 33
22 Aug after 35.0 °C 27 % 28 km/h 0.0 mm Very high 41

Its twins: fires that started in the same weather

It started with an FWI of 45.6, a minimum humidity of 19% and more than two months without rain. Fires in the area that started in weather like this since 2016: 30.

FWI at the start 45.6
Minimum humidity 19 %
Days without rain 60+
this fire chosen twins rest of the area
Almost identicalSimilar

Outlines of the closest twins

Zeboudja fire, August 2019
309 ha 2 days FWI 49.2 Min. humidity 20 % 48 km away, in 2019

First rain (1 mm or more) after it ended: none in the following ten days.

See its page Compare with this fire

What happened to them

2 days
median duration
219 ha
median area
13 %
went past 1,000 ha
1.8 mm
rain at the end (median; 12 of 30 had it)

It was 9.8 times larger than the median of its twins and lasted 3 days, against 2 days.

Only 2 of its 30 twins burned more. The weather on the first day does not explain everything: the wind in the following days, the fuel and the firefighting also count. In 18 of 30, not even 1 mm fell in the ten days after the end: they went out without rain. In the rest, the first rainy day brought a median of 1.8 mm.

This is a bank of analogues: it shows what usually happens, not what will happen. With fewer than 15 twins we give no figures. How we calculate it

How it ended

—first rain
—no rain in ten days
45km/h · max. gust

It was considered over on 12 Aug, and not even 1 mm fell in the following ten days: it went out without rain. Twins with rain when they ended: 12 of 30, with a median of 1.8 mm.

Weather on this page: Open-Meteo.com (CC BY 4.0) · Copernicus Climate Change Service (ERA5)

How a twin is chosen

  • Same area: fires that have already ended, less than 250 km from this one, since 2016.
  • Same start: we compare the FWI on the first day, the minimum humidity that day and the run of days without rain before it. The slider sets how much they may differ.
  • Only pages with final weather data (ERA5 reanalysis) calculated in the same way as this fire’s; agricultural and grass burns and pages with data under review are left out.
  • Fires burning at the same time as this one (a week before or after) are left out: they share the same spell of weather and do not count as a precedent.
  • They are sorted by similarity, and the outlines of the first five are drawn.

How we calculate it

Before and after, from space

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

Before · 3 Aug 2020
After · 19 Aug 2020

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 12 August 2020 the air beside the fire reached 24 µg/m³ of PM2.5. That day averaged 19: 1.3 times the WHO daily guideline (15).

PM2.5 peak24 µg/m³
Days over the guideline3 days
PM1039 µg/m³
8 Aug10 Aug12 Aug14 Aug
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 · 13Every 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 Algeria

Frequently asked questions

How long did the El Marsa fire last?
Copernicus dates it between 10 August 2020 and 12 August 2020: 3 days between the first and last image with fire.
How much area did it burn?
The perimeter Copernicus measured from satellite imagery is 2,153 hectares (21.5 km²). Official national figures may differ.
Which municipalities burned?
The fire only entered El Marsa (2,158 ha, 18 %).
Did the fire reach a town?
The fire started in El Marsa and came within 1.3 km of its centre. That is the distance from the perimeter, or the nearest hotspot, to the point marking the centre; it does not mean it entered the houses.
What was the weather like?
During the fire the temperature reached 37.7 °C, humidity dropped to 19 % and gusts hit 45 km/h. The fire danger index (FWI) reached 46, class Very high.
Where does this data come from?
From the EFFIS (Copernicus) burnt perimeter, NASA FIRMS VIIRS hotspots and the administrative boundaries of Algeria (geoBoundaries). It is not an official report.
How did the fires that started in similar weather in this area end?
Fires less than 250 km away that started since 2016 with a similar FWI, humidity and dry spell: 30. Their median duration was 2 days and their median area 219 ha; 13 % went past 1,000 ha. Only 2 of its 30 twins burned more. The weather on the first day does not explain everything: the wind in the following days, the fuel and the firefighting also count. In 18 of 30, not even 1 mm fell in the ten days after the end: they went out without rain. In the rest, the first rainy day brought a median of 1.8 mm.

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.

Emergency number: 14 · 1021 · Emergency number and official warnings

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 With cross-checks and a citable version

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
What do you think is wrong?

We will only use your email to reply about this report. Privacy. This is not an emergency service: if there is a fire now, call 14 · 1021.

How we know this
  • Perimeter: EFFIS (Copernicus), mapped on satellite imagery.
  • Dates from the perimeter: the VIIRS detections inside it did not change them. 13 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 2020, 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 and land cover come from the Copernicus European Forest Fire Information System (EFFIS), measured on MODIS and Sentinel-2 imagery and published under CC BY 4.0. 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-ShareAlike 2.0). The area per municipality is computed by WorldFires by crossing the perimeter with those boundaries, so it may differ slightly from each country’s official figure.