Skip to content
worldfires
PT · Portugal · –

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.

Burnt area
113ha
Copernicus perimeter
Duration
2days
18 Feb 2023 – 19 Feb 2023
Freguesias hit
2
freguesias
Started on
18 Feb
2023
Heat detections
1
in a single hotspot: 5 MW
Danger at start
6
Low · FWI index
Average daily power
5MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 18 Feb19 Feb

How it evolved, day by day

19 Feb 2023 · 5 MW · 1

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

The weather it burned in

14°high
30km/h · peak gust
37%lowest humidity

It had gone 29 days without rain (1 mm or more) when it started. Rain came after the fire: 3.1 mm on 20 Feb.

This area had burned before

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

What happened to each freguesia

  1. Chã 701 inhabitants · 1.3 km from the centre where it started
    103 ha reached on 19 Feb
    2.0 %
  2. Montalegre e Padroso 1,772 inhabitants · 1.8 km from the centre
    10 ha
    0.3 %

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.

When each one burned

1 30 ha 2 80 ha
18 Feb19 Feb
negligence
  1. 1 Montalegre Chã 18 February 2023 · 13:34 30 ha · extinguished on 18 February 2023 · cause: negligence
  2. 2 Montalegre Chã 18 February 2023 · 17:20 80 ha · extinguished on 19 February 2023 · cause: negligence

Total according to ICNF: 110 ha, 97 % of the 113 ha in the satellite perimeter.

ICNF (Instituto da Conservação da Natureza e das Florestas). This is the agency’s operational record: its figures may be revised when the year’s statistics are closed.

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)
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 start 6.3
Minimum humidity 37 %
Days without rain 29
this fire chosen twins rest of the area
Almost identicalSimilar

Outlines of the closest twins

Montalegre fire, January 2022
120 ha 2 days FWI 5.9 Min. humidity 36 % 19 km away, in 2022

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

What happened to them

2 days
median duration
172 ha
median area
0 %
went past 1,000 ha
5.4 mm
rain at the end (median; 14 of 20 had it)

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.

How we calculate it

Before and after, from space

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

Before · 11 Feb 2023
After · 26 Feb 2023

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 peak27 µg/m³
Days over the guideline2 days
PM1048 µg/m³
Optical depth0.76
16 Feb18 Feb20 Feb22 Feb
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 · 1Every 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 Portugal

Frequently asked questions

How long did the Montalegre fire last?
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.

Emergency number: 112 · 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.

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 112.

How 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.

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. 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.