Montalegre fire, 18 February 2023
Chã, Montalegre e Padroso
Out · last detection 19 Feb 2023, 12:40 UTC
The fire started on 18 February 2023 in Chã, Portugal, and satellites saw it burning for 2 days. Copernicus mapped a burnt perimeter of 113 hectares from satellite imagery, spread across 2 freguesias. According to ICNF, the largest of the 2 recorded fires was detected on 18 February 2023 at 17:20 and declared extinguished on 19 February 2023.
It is the 60th largest in Montalegre since 2016 (of 65 with a page). Number 33 in Portugal in 2023, of 39.
The power measured by the satellite is low (5.0 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
14.0°C · 46% RH
High of 14.0 °C and minimum humidity of 46% on 19 February 2023; gusts of 30 km/h on 19 February 2023.
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
Matches: 110 ha in the official record (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
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 land66 %
Scrub and transitional woodland33 %
Agricultural areas0.9 %
Land cover inside the perimeter according to Corine Land Cover, as reported by Copernicus.
Official record
Complex of 2 fires according to ICNF
According to ICNF, 2 fires started inside this perimeter on these dates, totalling 110 ha (the satellite measured 113 ha).
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)
18 Feb
12.8 °C
37 %
26 km/h
0.0 mm
Low 6
19 Feb
14.0 °C
46 %
30 km/h
0.1 mm
Low 6
20 Feb after
12.9 °C
50 %
24 km/h
3.1 mm
Very low 5
Its twins: fires that started in the same weather
It started with an FWI of 6.3, a minimum humidity of 37% and 29 days without rain. Fires in the area that started in weather like this since 2016: 20.
FWI at the start6.3
Minimum humidity37 %
Days without rain29
this firechosen twinsrest of the area
Almost identicalSimilar
Outlines of the closest twins
This fire · Montalegre fire, 18 February 2023
113 ha2 daysFWI 6.3Min. humidity 37 %
Montalegre fire, January 2022
120 ha2 daysFWI 5.9Min. humidity 36 %19 km away, in 2022
First rain (1 mm or more) after it ended: none in the following ten days.
It stayed below its twins: 113 ha against a median of 172 ha. It lasted 2 days, against 2 days.
In 6 of 20, 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 5.4 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
3.1 mmfirst rain
20 Febthe day after it ended
30km/h · max. gust
It was considered over on 19 Feb, and on 20 Feb 3.1 mm fell. We do not know whether the rain or the firefighters put it out. Twins with rain when they ended: 14 of 20, with a median of 5.4 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 · 11 Feb 2023
After · 26 Feb 2023
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 20 February 2023 the air beside the fire reached 27 µg/m³ of PM2.5. That day averaged 23: 1.5 times the WHO daily guideline (15).
PM2.5 peak27µg/m³
Days over the guideline2days
PM1048µg/m³
Optical depth0.76
WHO 15
16 Feb18 Feb20 Feb22 Feb
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· 1Every 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 18 February 2023 and 19 February 2023: 2 days between the first and last image with fire. According to ICNF, the largest of the 2 recorded fires was detected on 18 February 2023 at 17:20 and declared extinguished on 19 February 2023.
How much area did it burn?
The perimeter Copernicus measured from satellite imagery is 113 hectares (1.1 km²). Official national figures may differ.
Which freguesias burned?
The fire entered 2 freguesias: Chã (103 ha, 2.0 %); Montalegre e Padroso (10 ha, 0.3 %).
Did the fire reach a town?
The fire started in Chã 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 14.0 °C, humidity dropped to 37 % and gusts hit 30 km/h. The fire danger index (FWI) reached 6, class 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: 20. Their median duration was 2 days and their median area 172 ha; 0 % went past 1,000 ha. In 6 of 20, 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 5.4 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. One Suomi-NPP VIIRS detection on those dates.
Compared with ICNF: 110 official ha against 113 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.