Aller fire, 31 December 2021 Aller
The fire started on 31 December 2021 in Aller, Spain, and satellites saw it burning for 4 days. Copernicus mapped a burnt perimeter of 187 hectares from satellite imagery, spread across a single municipality.
It is the 94th largest in Asturias since 2016 (of 225 with a page). Number 72 in Spain in 2021, of 124.
The power measured by the satellite is low (7.7 MW in the strongest hotspot), more typical of grass or stubble burning, or a slow surface fire, than of a large crown fire.
Compare with…
- Burnt area
- 187ha
- Copernicus perimeter
- Duration
- 4days
- 31 Dec 2021 – 3 Jan 2022
- Municipalities hit
- 1
- municipalities
- Started on
- 31 Dec
- 2021
- Heat detections
- 2
- in a single hotspot: 8 MW
- Danger at start
- 0
- Very low · FWI index
- Average daily power
- 13MW
- detected power per day, on average
Where it burned
How it evolved, day by day
3 Jan 2022 · 13 MW · 2
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 3 days without rain (1 mm or more) when it started. Rain came after the fire: 17.0 mm on 4 Jan.
This area had burned before
No earlier perimeters overlap this fire since 2016, when the satellite record begins.
What happened to each town
-
187 ha reached on 3 Jan0.5 %
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 land67 %
- Broadleaved forest33 %
Land cover inside the perimeter according to Corine Land Cover, as reported by Copernicus.
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) |
|---|---|---|---|---|---|
| 31 Dec | 11.9 °C | 55 % | 38 km/h | 0.0 mm | Very low 0 |
| 1 Jan | 11.9 °C | 53 % | 42 km/h | 0.1 mm | Very low 1 |
| 2 Jan | 12.8 °C | 58 % | 42 km/h | 0.0 mm | Very low 1 |
| 3 Jan | 10.2 °C | 74 % | 44 km/h | 0.0 mm | Very low 1 |
| 4 Jan after | 8.3 °C | 84 % | 59 km/h | 17.0 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 31 December 2021 the air beside the fire reached 16 µg/m³ of PM2.5, but no daily average passed the WHO 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 · 2Every 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 Aller fire last?
- According to the heat detections seen by satellite inside the perimeter, it burned from 31 December 2021 to 3 January 2022 (4 days). The perimeter dates it from 31 December 2021 to 1 January 2022.
- How much area did it burn?
- The perimeter Copernicus measured from satellite imagery is 187 hectares (1.9 km²). Official national figures may differ.
- Which municipalities burned?
- The fire only entered Aller (187 ha, 0.5 %).
- Did the fire reach a town?
- The fire started in Aller and came within 1.7 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 11.9 °C, humidity dropped to 53 % and gusts hit 42 km/h. The fire danger index (FWI) reached 1, class Very low.
- Where does this data come from?
- From the EFFIS (Copernicus) burnt perimeter, NASA FIRMS VIIRS hotspots and the administrative boundaries of Spain (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 ›
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 31 December 2021 to 1 January 2022. 2 Suomi-NPP VIIRS detections on those dates.
- We have not matched this page with any official record.
- 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 (Creative Commons Attribution 4.0 International (CC BY 4.0)). 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.