The fire started on 10 January 2021 in Valdreu, Portugal, and satellites saw it burning for 1 day. Copernicus mapped a burnt perimeter of 111 hectares from satellite imagery, spread across a single freguesia.
It is the 14th largest in Vila Verde since 2016 (of 14 with a page). Number 27 in Portugal in 2021, of 30.
matches the official recordwith caveatssatellite onlymodel
When copying, the sentence is
Tick the figures you want: they make up the lede and the CSV.
Burned area
with caveats
111ha
Perimeter published by EFFIS (Copernicus).
This page111ICNF74
Source
EFFIS (Copernicus)
Date
perimeter revised on 26 January 2022
+− cross-check
ICNF: 74 ha (matched records: 2). Difference between the page and the official record: +50.2%. Matched on 1 November 2026. The two figures differ a lot, so these may not be exactly the same fire: take them as nearby records.
Duration by satellite
satellite only
1day
10 Jan 2021 to 10 Jan 2021: first and last day with fire on the page.
Source
EFFIS (Copernicus) · NASA FIRMS · VIIRS
Date
10 Jan 2021 – 10 Jan 2021
+− cross-check
Satellites pass a few times a day and cloud or smoke can hide the fire: a lack of detections is not an official extinction. Each country’s emergency service declares a fire contained or out.
Start
satellite only
10 Jan 2021
First day with fire seen by the satellites or the perimeter.
Source
EFFIS (Copernicus) · NASA FIRMS · VIIRS
Date
10 Jan 2021
+− cross-check
The two figures differ a lot, so these may not be exactly the same fire: take them as nearby records.
Danger at the start
model
1.2FWI · very low
Fire Weather Index (Canadian system) computed by WorldFires for the day the fire started. Consecutive days without rain before: 9.
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
7.8°C · 49% RH
High of 7.8 °C and minimum humidity of 49% on 10 January 2021; gusts of 48 km/h on 10 January 2021.
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
· reconstructedweather
Weather and FWI computed from the ERA5 reanalysis
· reconstructedofficial
Matched with the official ICNF record
Nearby records with very different figures: 74 ha (records: 2).
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
We have the Copernicus perimeter for this fire, but the VIIRS sensors did not capture it in enough detail: no day-by-day evolution, but the split by freguesia is there.
Burnt area
111ha
Copernicus perimeter
Duration
1day
10 Jan 2021 – 10 Jan 2021
Freguesias hit
1
freguesias
Started on
10 Jan
2021
Danger at start
1
Very low · FWI index
Natura 2000
0%
of the perimeter is protected land
Where it burned
The weather it burned in
8°high
48km/h · peak gust
49%lowest humidity
It had gone 9 days without rain (1 mm or more) when it started. Rain came after the fire: 2.0 mm on 19 Jan.
This area had burned before
33% of the perimeter overlaps earlier fires recorded since 2016: 27 ha in 2018, 10 ha in 2019.
What happened to each freguesia
Valdreu434 inhabitants · 0.8 km from the centrewhere it started
111 ha
6.2 %
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.
Natura 2000 sites (European Environment Agency, 2024 release) crossed by the perimeter.
Land cover inside the perimeter according to Corine Land Cover, as reported by Copernicus.
Official record
Several official records match this area
According to ICNF, 2 fires started inside this perimeter on these dates, totalling 74 ha (the satellite measured 111 ha). The two figures differ a lot, so these may not be exactly the same fire: take them as nearby records.
ICNF records each fire that started at a different time or place separately; the satellite sees a single burned area, so this page groups them together. The numbers on the map show where each one started.
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)
10 Jan
7.8 °C
49 %
48 km/h
0.0 mm
Very low 1
11 Jan after
8.8 °C
47 %
35 km/h
0.0 mm
Very low 1
12 Jan after
9.8 °C
47 %
18 km/h
0.0 mm
Very low 1
13 Jan after
10.8 °C
44 %
17 km/h
0.0 mm
Very low 1
14 Jan after
11.1 °C
65 %
28 km/h
0.0 mm
Very low 2
15 Jan after
11.4 °C
49 %
30 km/h
0.0 mm
Very low 2
16 Jan after
12.6 °C
44 %
22 km/h
0.0 mm
Very low 2
17 Jan after
13.8 °C
58 %
25 km/h
0.0 mm
Very low 2
18 Jan after
15.0 °C
49 %
26 km/h
0.0 mm
Very low 2
19 Jan after
9.8 °C
62 %
73 km/h
2.0 mm
Very low 4
Its twins: fires that started in the same weather
It started with an FWI of 1.2, a minimum humidity of 49% and 9 days without rain. Fires in the area that started in weather like this since 2016: 49.
FWI at the start1.2
Minimum humidity49 %
Days without rain9
this firechosen twinsrest of the area
Almost identicalSimilar
Outlines of the closest twins
This fire · Valdreu fire, January 2021
111 ha1 dayFWI 1.2Min. humidity 49 %
Melgaço fire, February 2023
135 ha1 dayFWI 2.9Min. humidity 48 %33 km away, in 2023
First rain (1 mm or more) after it ended: 12.5 mm on 21 Feb.
It burned an area similar to its twins (111 ha against a median of 148 ha) and lasted 1 day, against 1 day.
In 6 of 49, 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 5.6 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
2.0 mmfirst rain
19 Jan9 days after it ended
48km/h · max. gust
It was considered over on 10 Jan, and on 19 Jan 2.0 mm fell. We do not know whether the rain or the firefighters put it out. Twins with rain when they ended: 43 of 49, with a median of 5.6 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 · 3 Jan 2021
After · 17 Jan 2021
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 January 2021 the air beside the fire reached 23 µg/m³ of PM2.5, but no daily average passed the WHO guideline (15).
PM2.5 peak23µg/m³
Days over the guideline0days
PM1031µg/m³
WHO 15
8 Jan10 Jan12 Jan
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)
Copernicus dates it between 10 January 2021 and 10 January 2021: 1 day between the first and last image with fire.
How much area did it burn?
The perimeter Copernicus measured from satellite imagery is 111 hectares (1.1 km²). Official national figures may differ.
Which freguesias burned?
The fire only entered Valdreu (111 ha, 6.2 %).
Did the fire reach a town?
The fire started in Valdreu and came within 0.8 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 7.8 °C, humidity dropped to 49 % and gusts hit 48 km/h. The fire danger index (FWI) reached 1, class Very low.
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: 49. Their median duration was 1 day and their median area 148 ha; 0 % went past 1,000 ha. In 6 of 49, 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 5.6 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. No Suomi-NPP VIIRS detections on those dates.
Compared with ICNF: 74 official ha against 111 ha of perimeter; similar, but with reservations.
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.