Portela e Extremo fire, September 2020
Portela e Extremo
Out · last detection 13 Sept 2020, 02:24 UTC
The fire started on 12 September 2020 in Portela e Extremo, Portugal, and satellites saw it burning for 2 days. Copernicus mapped a burnt perimeter of 114 hectares from satellite imagery, spread across a single freguesia. According to ICNF, it was detected on 12 September 2020 at 22:18 and declared extinguished on 13 September 2020.
It is the 24th largest in Arcos de Valdevez since 2016 (of 29 with a page). Number 63 in Portugal in 2020, of 67.
The power measured by the satellite is low (11.2 MW in the strongest hotspot), more typical of grass or stubble burning, or a slow surface fire, than of a large crown fire.
This is an index computed from weather model data, not a measurement of the fire nor an official warning. Danger warnings are issued by each country’s authority. Emergency number and official warnings ›
Weather during the fire
model
31.8°C · 28% RH
High of 31.8 °C and minimum humidity of 28% on 12 September 2020; gusts of 36 km/h on 13 September 2020.
These are model values for a cell of about 25 km, not from a weather station: they may differ from what was measured on the ground.
ⓘThis page’s change log has been kept since 24 October 2026: every night what it publishes is compared and the difference is logged. Anything earlier is reconstructed from each source’s date and marked as reconstructed.
Show
· reconstructedofficial
Matched with the official ICNF record
Matches: 113 ha in the official record (records: 1).
A version keeps the area, dates, name and official record; the area as it was logged (changes under 2% are not logged). The map, hotspots and weather always show today’s data.
Citation
A lede of about 60 words figures only, no adjectives
Portela e Extremo323 inhabitants · fire reached the centrewhere it started
114 hareached on 13 Sept
9.6 %
Burnt area inside each freguesia, 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
Other natural land97 %
Agricultural areas1.7 %
Scrub and transitional woodland0.9 %
Land cover inside the perimeter according to Corine Land Cover, as reported by Copernicus.
Official record
According to ICNF, this fire started on 12 September 2020 and burned 113 ha (the satellite measured 114 ha).
Arcos de ValdevezPortela12 September 2020 · 22:18113 ha· extinguished on 13 September 2020· cause: negligence
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
31.8 °C
28 %
22 km/h
0.0 mm
High 22
13 Sept
31.0 °C
28 %
36 km/h
0.1 mm
High 23
14 Sept after
22.8 °C
60 %
46 km/h
4.0 mm
Very low 3
Its twins: fires that started in the same weather
It started with an FWI of 21.6, a minimum humidity of 28% and 21 days without rain. Fires in the area that started in weather like this since 2016: 36.
FWI at the start21.6
Minimum humidity28 %
Days without rain21
this firechosen twinsrest of the area
Almost identicalSimilar
Outlines of the closest twins
This fire · Portela e Extremo fire, September 2020
114 ha2 daysFWI 21.6Min. humidity 28 %
Monção e Troviscoso fire, October 2018
154 ha1 dayFWI 21.7Min. humidity 28 %12 km away, in 2018
First rain (1 mm or more) after it ended: 16.3 mm on 11 Oct.
It stayed below its twins: 114 ha against a median of 369 ha. It lasted 2 days, against 2 days.
In 8 of 36, 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 14.3 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
4.0 mmfirst rain
14 Septthe day after it ended
36km/h · max. gust
It was considered over on 13 Sept, and on 14 Sept 4.0 mm fell. We do not know whether the rain or the firefighters put it out. Twins with rain when they ended: 28 of 36, with a median of 14.3 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.
Drag the line to compare the same ground before the fire and after it.
↔
Before · 5 Sept 2020
After · 20 Sept 2020
Sentinel-2 did not pass over on that day. Try another date, or use false colour, which is daily.
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 13 September 2020 the air beside the fire reached 28 µg/m³ of PM2.5. That day averaged 16: 1.1 times the WHO daily guideline (15).
PM2.5 peak28µg/m³
Days over the guideline1day
PM1033µg/m³
WHO 15
10 Sept12 Sept14 Sept16 Sept
GoodFairModeratePoorVery poorExtremely 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· 8Every satellite heat detection, one by one, with time, satellite, power and coordinates.›
⬇ Download CSVTimes in UTC. Each detection is a 375 m pixel: a large fire yields hundreds per pass.
Copernicus dates it between 12 September 2020 and 13 September 2020: 2 days between the first and last image with fire. According to ICNF, it was detected on 12 September 2020 at 22:18 and declared extinguished on 13 September 2020.
How much area did it burn?
The perimeter Copernicus measured from satellite imagery is 114 hectares (1.1 km²). Official national figures may differ.
Which freguesias burned?
The fire only entered Portela e Extremo (114 ha, 9.6 %).
Did the fire reach a town?
The fire started in Portela e Extremo and reached its centre: the point marking it was inside the burnt area or less than 500 metres from it. That does not mean houses burned.
What was the weather like?
During the fire the temperature reached 31.8 °C, humidity dropped to 28 % and gusts hit 36 km/h. The fire danger index (FWI) reached 23, class High.
Where does this data come from?
From the EFFIS (Copernicus) burnt perimeter, NASA FIRMS VIIRS hotspots and the administrative boundaries of Portugal (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: 36. Their median duration was 2 days and their median area 369 ha; 22 % went past 1,000 ha. In 8 of 36, 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 14.3 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.
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 errorHow we know this›
Perimeter: EFFIS (Copernicus), mapped on satellite imagery.
Dates from the perimeter: the VIIRS detections inside it did not change them. 8 Suomi-NPP VIIRS detections on those dates.
Compared with ICNF: 113 official ha against 114 ha of perimeter; they agree within 25%.
Weather: Copernicus ERA5 reanalysis at the fire location, in cells of about 25 km.
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. Freguesia boundaries come from geoBoundaries ADM3 (CC0 1.0 Universal (CC0 1.0) Public Domain Dedication). The area per freguesia is computed by WorldFires by crossing the perimeter with those boundaries, so it may differ slightly from each country’s official figure.