Arcos de Valdevez fire, 4 August 2025 Rio Frio, Senharei
The fire started on 4 August 2025 in Rio Frio, Portugal, and satellites saw it burning for 3 days. Copernicus mapped a burnt perimeter of 300 hectares from satellite imagery, spread across 2 municipalities. According to ICNF, the largest of the 2 recorded fires was detected on 3 August 2025 at 20:13 and declared extinguished on 5 August 2025.
It is the 10th largest in Arcos de Valdevez since 2016 (of 29 with a page). Number 48 in Portugal in 2025, of 85.
Compare with…
- Burnt area
- 300ha
- Copernicus perimeter
- Duration
- 3days
- 4 Aug 2025 – 6 Aug 2025
- Municipalities hit
- 2
- freguesias
- Started on
- 4 Aug
- 2025
- Heat detections
- 31
- in a single hotspot: 45 MW
- Danger at start
- 26
- High · FWI index
- Average daily power
- 152MW
- detected power per day, on average
Where it burned
How it evolved, day by day
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 14 days without rain (1 mm or more) when it started.
This area had burned before
57% of the perimeter overlaps earlier fires recorded since 2016: 156 ha in 2017, 25 ha in 2021, 1 ha in 2023, 5 ha in 2024. Part of it burned more than once, so the yearly figures add up to more than the 172 ha that had burned before.
What happened to each town
-
267 ha reached on 4 Aug14 %
-
Senharei 164 inhabitants · 1.0 km from the centre33 ha reached on 4 Aug4.3 %
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
- Scrub and transitional woodland47 %
- Other natural land36 %
- Agricultural areas11 %
- Broadleaved forest5.9 %
Natura 2000 protected area affected: 20 %
- LIC Corno do Bico PTCON0040
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.
Complex of 2 fires according to ICNF
According to ICNF, 2 fires started inside this perimeter on these dates, totalling 283 ha (the satellite measured 300 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.
- 1 Arcos de Valdevez Rio Frio 3 August 2025 · 20:13 254 ha · extinguished on 5 August 2025 · cause: negligence
- 2 Arcos de Valdevez Rio Frio 5 August 2025 · 16:10 29 ha · extinguished on 6 August 2025 · cause: rekindling
Total according to ICNF: 283 ha, 94 % of the 300 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) |
|---|---|---|---|---|---|
| 4 Aug | 32.6 °C | 29 % | 27 km/h | 0.0 mm | High 26 |
| 5 Aug | 34.0 °C | 28 % | 23 km/h | 0.0 mm | High 26 |
| 6 Aug | 27.9 °C | 44 % | 31 km/h | 0.0 mm | High 23 |
| 7 Aug after | 27.0 °C | 45 % | 27 km/h | 0.0 mm | Moderate 21 |
| 8 Aug after | 26.9 °C | 55 % | 26 km/h | 0.0 mm | Moderate 17 |
| 9 Aug after | 29.5 °C | 53 % | 26 km/h | 0.1 mm | Moderate 18 |
| 10 Aug after | 29.2 °C | 39 % | 40 km/h | 0.0 mm | High 23 |
| 11 Aug after | 29.8 °C | 37 % | 20 km/h | 0.0 mm | Moderate 20 |
| 12 Aug after | 27.4 °C | 41 % | 41 km/h | 0.1 mm | High 23 |
| 13 Aug after | 27.8 °C | 45 % | 32 km/h | 0.0 mm | High 23 |
| 14 Aug after | 29.6 °C | 38 % | 32 km/h | 0.0 mm | High 23 |
| 15 Aug after | 23.8 °C | 55 % | 41 km/h | 0.0 mm | Moderate 21 |
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 6 August 2025 the air beside the fire reached 122 µg/m³ of PM2.5. That day averaged 57: 3.8 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 · 31Every satellite heat detection, one by one, with time, satellite, power and coordinates.
| Date and time | Satellite | FRP (MW) | Lat | Lon |
|---|
Other fires nearby
- 6,662 haArcos de Valdevez Soajo8 August 2016 · 9 days · 15 km away
- 9,224 haCabração e Moreira do LimaAugust 2016 · 5 days · 17 km away
- 3,893 haMonção MerufeOctober 2017 · 2 days · 19 km away
- 7,225 haPonte da Barca Entre Ambos-os-Rios, Ermida e GermilJuly 2025 · 11 days · 21 km away
- 2,698 haNogueira, Meixedo e Vilar de MurtedaAugust 2016 · 4 days · 25 km away
- 3,074 haEntrimoSeptember 2016 · 7 days · 27 km away
Frequently asked questions
- How long did the Arcos de Valdevez fire last?
- According to the heat detections seen by satellite inside the perimeter, it burned from 4 August 2025 to 6 August 2025 (3 days). The perimeter dates it from 4 August 2025 to 5 August 2025. According to ICNF, the largest of the 2 recorded fires was detected on 3 August 2025 at 20:13 and declared extinguished on 5 August 2025.
- How much area did it burn?
- The perimeter Copernicus measured from satellite imagery is 300 hectares (3.0 km²). Official national figures may differ.
- Which municipalities burned?
- The fire entered 2 municipalities: Rio Frio (267 ha, 14 %); Senharei (33 ha, 4.3 %).
- Did the fire reach a town?
- The fire started in Rio Frio 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 34.0 °C, humidity dropped to 28 % and gusts hit 27 km/h. The fire danger index (FWI) reached 26, 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 adjusted with the VIIRS detections inside the perimeter, which said 4 August 2025 to 5 August 2025. 31 Suomi-NPP VIIRS detections on those dates.
- Compared with ICNF: 283 official ha against 300 ha of perimeter; they agree within 25%.
- Weather: Copernicus ERA5 reanalysis at the fire location, in cells of about 25 km.
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.