Montalegre fire, 12 September 2016 Santo André, Gralhas
The fire started on 12 September 2016 in Gralhas, Portugal, and satellites saw it burning for 1 day. Copernicus mapped a burnt perimeter of 979 hectares from satellite imagery, spread across 2 municipalities. According to ICNF, it was detected on 12 September 2016 at 17:54 and declared extinguished on 13 September 2016.
It is the 3th largest in Montalegre since 2016 (of 64 with a page). Number 34 in Portugal in 2016, of 180.
Compare with…
- Burnt area
- 979ha
- Copernicus perimeter
- Duration
- 1day
- 12 Sept 2016 – 12 Sept 2016
- Municipalities hit
- 2
- freguesias
- Started on
- 12 Sept
- 2016
- Heat detections
- 14
- in a single hotspot: 61 MW
- Danger at start
- 25
- High · FWI index
- Average daily power
- 590MW
- detected power per day, on average
Where it burned
How it evolved, day by day
12 Sept 2016 · 590 MW · 14
Fire radiative power detected each day, in megawatts, and number of hotspots. The magenta bar marks the peak day.
The weather it burned in
It had gone 16 days without rain (1 mm or more) when it started. Rain came after the fire: 28.0 mm on 13 Sept.
This area had burned before
No earlier perimeters overlap this fire since 2016, when the satellite record begins.
How big is it?
London boundary: geoBoundaries · Office for National Statistics (Open Government Licence v3.0).
Lisbon boundary: geoBoundaries · geoBoundaries, DG Territory (CC0 1.0).
Paris boundary: geoBoundaries · Institut national de l'information géographique et forestière (IGN-F) (Etalab Open License 2.0).
Madrid boundary: geoBoundaries · Open Data ESRI, IGN Central Registry of Cartography Area (CC BY 4.0).
This compares size, not location: both shapes are at the same scale, north up, centred on each other.
What happened to each town
-
Santo André fire reached the centre569 ha30 %
-
406 ha reached on 12 Sept19 %
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
- Other natural land73 %
- Agricultural areas26 %
- Broadleaved forest0.7 %
Land cover inside the perimeter according to Corine Land Cover, as reported by Copernicus.
People and buildings inside the perimeter
GHSL 2015Inside the perimeter there was no noticeable built-up land and almost nobody lived there (GHSL 2015, 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
Official record
According to ICNF, this fire started on 12 September 2016 and burned 940 ha (the satellite measured 979 ha).
- Montalegre Gralhas 12 September 2016 · 17:54 940 ha · extinguished on 13 September 2016 · cause: negligence
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) |
|---|---|---|---|---|---|
| 12 Sept | 26.5 °C | 35 % | 50 km/h | 0.0 mm | High 25 |
| 13 Sept after | 16.2 °C | 62 % | 59 km/h | 28.0 mm | Very low 0 |
Before and after, from space
Drag the line to compare the same ground before the fire and after it.
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 · CopernicusOn 13 September 2016 the air beside the fire reached 26 µg/m³ of PM2.5. That day averaged 19: 1.2 times the WHO daily guideline (15).
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 · 14Every satellite heat detection, one by one, with time, satellite, power and coordinates.
| Date and time | Satellite | FRP (MW) | Lat | Lon |
|---|
Other fires nearby
Frequently asked questions
- How long did the Montalegre fire last?
- Copernicus dates it between 12 September 2016 and 12 September 2016: 1 day between the first and last image with fire. According to ICNF, it was detected on 12 September 2016 at 17:54 and declared extinguished on 13 September 2016.
- How much area did it burn?
- The perimeter Copernicus measured from satellite imagery is 979 hectares (9.8 km²). Official national figures may differ.
- Which municipalities burned?
- The fire entered 2 municipalities: Santo André (569 ha, 30 %); Gralhas (406 ha, 19 %).
- Did the fire reach a town?
- The fire reached the centre of Santo André: 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 26.5 °C, humidity dropped to 35 % and gusts hit 50 km/h. The fire danger index (FWI) reached 25, 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.
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 ›
- ICNF · Instituto da Conservação da Natureza e das Florestas ↗
- ANEPC · Proteção Civil ↗
- Fogos.pt (ocorrências em tempo real) ↗
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.
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
How we know this
- Perimeter: EFFIS (Copernicus), mapped on satellite imagery.
- Dates from the perimeter: the VIIRS detections inside it did not change them. 14 Suomi-NPP VIIRS detections on those dates.
- Compared with ICNF: 940 official ha against 979 ha of perimeter; they agree within 25%.
- 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 2015, 100 m cells), summed inside the perimeter: an estimate of what was there, not a damage count.
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 (CC0 1.0 Universal (CC0 1.0) Public Domain Dedication). 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.