Alfena fire, August 2022 Água Longa, Alfena
The fire started on 29 August 2022 in Alfena, Portugal, and satellites saw it burning for 3 days. Copernicus mapped a burnt perimeter of 108 hectares from satellite imagery, spread across 2 municipalities. According to ICNF, it was detected on 29 August 2022 at 14:13 and declared extinguished on 29 August 2022.
Number 100 in Portugal in 2022, of 107.
- Burnt area
- 108ha
- Copernicus perimeter
- Duration
- 3days
- 29 Aug 2022 – 31 Aug 2022
- Municipalities hit
- 2
- freguesias
- Started on
- 29 Aug
- 2022
- Heat detections
- 3
- in a single hotspot: 50 MW
- Danger at start
- 20
- Moderate · FWI index
- Energy released
- 104MW
- sum of detected power
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 12 days without rain (1 mm or more) when it started. Rain came after the fire: 1.4 mm on 4 Sept.
This area had burned before
No earlier perimeters overlap this fire since 2016, when the satellite record begins.
What happened to each town
-
Água Longa 2,342 inhabitants · 1.3 km from the town97 ha reached on 29 Aug7.6 %
-
11 ha reached on 29 Aug1.0 %
Burnt area inside each municipality, from crossing the official perimeter with administrative boundaries. The distance is from the town centre to the nearest fire: staying a kilometre away does not mean it reached the houses.
What burned
- Scrub and transitional woodland81 %
- Broadleaved forest13 %
- Artificial surfaces5.7 %
Land cover inside the perimeter according to Corine Land Cover, as reported by Copernicus.
Official record
According to ICNF, this fire started on 29 August 2022 and burned 105 ha (the satellite measured 108 ha).
- Valongo Alfena 29 August 2022 · 14:13 105 ha · extinguished on 29 August 2022 · cause: unknown
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) |
|---|---|---|---|---|---|
| 29 Aug | 24.1 °C | 58 % | 35 km/h | 0.0 mm | Moderate 20 |
| 30 Aug | 23.1 °C | 56 % | 30 km/h | 0.0 mm | Moderate 18 |
| 31 Aug | 23.0 °C | 60 % | 33 km/h | 0.0 mm | Moderate 19 |
| 1 Sept after | 22.9 °C | 67 % | 32 km/h | 0.0 mm | Moderate 16 |
| 2 Sept after | 22.2 °C | 64 % | 35 km/h | 0.1 mm | Moderate 18 |
| 3 Sept after | 22.1 °C | 50 % | 30 km/h | 0.0 mm | Moderate 17 |
| 4 Sept after | 22.1 °C | 64 % | 49 km/h | 1.4 mm | Moderate 12 |
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 27 August 2022 the air beside the fire reached 22 µg/m³ of PM2.5. That day averaged 16: 1.1 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 · 3Every 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 Alfena fire last?
- Copernicus dates it between 29 August 2022 and 31 August 2022: 3 days between the first and last image with fire. According to ICNF, it was detected on 29 August 2022 at 14:13 and declared extinguished on 29 August 2022.
- How much area did it burn?
- The perimeter Copernicus measured from satellite imagery is 108 hectares (1.1 km²). Official national figures may differ.
- Which municipalities burned?
- The fire entered 2 municipalities: Água Longa (97 ha, 7.6 %); Alfena (11 ha, 1.0 %).
- Did the fire reach a town?
- The closest fire to a town centre came within 1.3 km of Água Longa. That is the distance to the perimeter or nearest hotspot; it does not mean it entered the houses.
- What was the weather like?
- During the fire the temperature reached 24.1 °C, humidity dropped to 56 % and gusts hit 35 km/h. The fire danger index (FWI) reached 20, class Moderate.
- 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
- ICNF · Instituto da Conservação da Natureza e das Florestas ↗
- ANEPC · Proteção Civil ↗
- Fogos.pt (ocorrências em tempo real) ↗
Satellite cross-check
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
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.