The fire started on 29 March 2023 in Tudanca, Spain, and satellites saw it burning for 3 days. Copernicus mapped a burnt perimeter of 237 hectares from satellite imagery, spread across 2 municipalities.
It is the 67th largest in Cantabria since 2016 (of 179 with a page). Number 52 in Spain in 2023, of 124.
The power measured by the satellite is low (13.8 MW in the strongest hotspot), more typical of grass or stubble burning, or a slow surface fire, than of a large crown fire.
matches the official recordwith caveatssatellite onlymodel
When copying, the sentence is
Tick the figures you want: they make up the lede and the CSV.
Burned area
with caveats
237ha
Perimeter published by EFFIS (Copernicus).
This page237EGIF (MITECO)412
Source
EFFIS (Copernicus)
Date
perimeter revised on 7 April 2023
+− cross-check
EGIF (MITECO): 412 ha (matched records: 2). Difference between the page and the official record: −42.4%. Matched on 1 November 2026. The two figures differ a lot, so these may not be exactly the same fire: take them as nearby records.
Duration by satellite
satellite only
3days
29 Mar 2023 to 31 Mar 2023: first and last day with fire on the page.
Source
EFFIS (Copernicus) · NASA FIRMS · VIIRS
Date
last detection: 31 Mar 2023, 02:07 UTC
+− cross-check
Satellites pass a few times a day and cloud or smoke can hide the fire: a lack of detections is not an official extinction. Each country’s emergency service declares a fire contained or out.
Start
satellite only
29 Mar 2023
First day with fire seen by the satellites or the perimeter.
Source
EFFIS (Copernicus) · NASA FIRMS · VIIRS
Date
29 Mar 2023
+− cross-check
The two figures differ a lot, so these may not be exactly the same fire: take them as nearby records.
Hotspots
satellite only
11
VIIRS detections at 375 m. Most intense hotspot: 14 MW.
Source
NASA FIRMS · VIIRS (Suomi NPP)
Date
29 Mar 2023 – 31 Mar 2023
+− cross-check
There is no official record to compare with. Each hotspot is a pixel detected in one satellite pass, not a separate fire.
The worst day
satellite only
73MW
Total radiative power on 30 March 2023; hotspots that day: 9.
Source
NASA FIRMS · VIIRS (FRP)
Date
30 Mar 2023
+− cross-check
Fire radiative power (FRP) measures the energy the fire gives off when the satellite passes. Added up by day, it compares intensity, not area.
Danger at the start
model
5.6FWI · low
Fire Weather Index (Canadian system) computed by WorldFires for the day the fire started. Consecutive days without rain before: 2.
This is an index computed from weather model data, not a measurement of the fire nor an official warning. Danger warnings are issued by each country’s authority. Emergency number and official warnings ›
Weather during the fire
model
22.8°C · 25% RH
High of 22.8 °C and minimum humidity of 25% on 29 March 2023; gusts of 45 km/h on 29 March 2023.
These are model values for a cell of about 25 km, not from a weather station: they may differ from what was measured on the ground.
ⓘThis page’s change log has been kept since 24 October 2026: every night what it publishes is compared and the difference is logged. Anything earlier is reconstructed from each source’s date and marked as reconstructed.
Show
· reconstructedofficial
Matched with the official EGIF (MITECO) record
Nearby records with very different figures: 412 ha (records: 2).
A version keeps the area, dates, name and official record; the area as it was logged (changes under 2% are not logged). The map, hotspots and weather always show today’s data.
Citation
A lede of about 60 words figures only, no adjectives
CSV for this fire tudanca-2023-03.csv · daily, no individual hotspots
fecha
focos_viirs
frp_mw
tmax_c
tmin_c
hr_min_pct
viento_max_kmh
racha_max_kmh
precip_mm
fwi
clase_fwi
dentro_del_incendio
2023-03-29
0
0
22.8
10.8
25
18.4
45.4
0.6
5.6
bajo
1
2023-03-30
9
73
17
8.4
46
15.3
43.6
0.3
4.8
muy_bajo
1
2023-03-31
2
4
13.7
8.2
55
17.1
41.4
2.3
0.6
muy_bajo
1
2023-04-01
0
0
9.2
5.9
73
18.9
57.6
7.1
0
muy_bajo
0
It is generated in your browser from this page’s data: one file per fire, aggregated by day and without individual hotspots.
Live widget for your story
It updates itself while the fire is still active and links to this page. Free, with the attribution shown at the bottom.
Sources for this page: EFFIS (Copernicus), NASA FIRMS (VIIRS), EGIF (MITECO), ERA5 (ECMWF/Copernicus C3S) · Open-Meteo.com (CC BY 4.0), GHSL (JRC). Open-Meteo.com · How we build fire pages: methodology
Burnt area
237ha
Copernicus perimeter
Duration
3days
29 Mar 2023 – 31 Mar 2023
Municipalities hit
2
municipalities
Started on
29 Mar
2023
Heat detections
11
in a single hotspot: 14 MW
Danger at start
6
Low · FWI index
Average daily power
39MW
detected power per day, on average
Where it burned
HOTSPOTS BY DAY
29 Mar31 Mar
Play back31 Mar 2023
How it evolved, day by day
30 Mar31 Mar
Fire radiative power detected each day, in megawatts, and number of hotspots. The magenta bar marks the peak day.
The weather it burned in
23°high
45km/h · peak gust
25%lowest humidity
It had gone 2 days without rain (1 mm or more) when it started. Rain came after the fire: 7.1 mm on 1 Apr.
This area had burned before
No earlier perimeters overlap this fire since 2016, when the satellite record begins.
What happened to each town
Tudanca154 inhabitants · 1.6 km from the centrewhere it started
201 hareached on 30 Mar
3.8 %
Cabuérniga976 inhabitants · 6.5 km from the centre
36 hareached on 30 Mar
0.4 %
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.
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.
People and buildings inside the perimeter
GHSL 2025
Built-up area< 0.1ha
Residents< 20
Inside the perimeter there was no noticeable built-up land and almost nobody lived there (GHSL 2025, 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. The GHSL 2025 epoch is a projection made from 2020 and earlier data.
According to EGIF (MITECO), 2 fires started inside this perimeter on these dates, totalling 412 ha (the satellite measured 237 ha). The two figures differ a lot, so these may not be exactly the same fire: take them as nearby records.
EGIF (MITECO) 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.
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 Mar
22.8 °C
25 %
45 km/h
0.6 mm
Low 6
30 Mar
17.0 °C
46 %
44 km/h
0.3 mm
Very low 5
31 Mar
13.7 °C
55 %
41 km/h
2.3 mm
Very low 1
1 Apr after
9.2 °C
73 %
58 km/h
7.1 mm
Very low 0
Its twins: fires that started in the same weather
It started with an FWI of 5.6, a minimum humidity of 25% and 2 days without rain. Fires in the area that started in weather like this since 2016: 25.
FWI at the start5.6
Minimum humidity25 %
Days without rain2
this firechosen twinsrest of the area
Almost identicalSimilar
Outlines of the closest twins
This fire · Tudanca fire, March 2023
237 ha3 daysFWI 5.6Min. humidity 25 %
Arenas de Iguña fire, February 2026
162 ha10 daysFWI 5.2Min. humidity 26 %30 km away, in 2026
First rain (1 mm or more) after it ended: 32.0 mm on 6 Mar.
It burned an area similar to its twins (237 ha against a median of 203 ha) and lasted 3 days, against 2 days.
All of them had rain in the ten days after the end: the first rainy day brought a median of 3.8 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
7.1 mmfirst rain
1 Aprthe day after it ended
45km/h · max. gust
It was considered over on 31 Mar, and on 1 Apr 7.1 mm fell. We do not know whether the rain or the firefighters put it out. Twins with rain when they ended: 25 of 25, with a median of 3.8 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.
Drag the line to compare the same ground before the fire and after it.
↔
Before · 22 Mar 2023
After · 7 Apr 2023
Sentinel-2 did not pass over on that day. Try another date, or use false colour, which is daily.
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 1 April 2023 the air beside the fire reached 30 µg/m³ of PM2.5. That day averaged 19: 1.2 times the WHO daily guideline (15).
PM2.5 peak30µg/m³
Days over the guideline1day
PM1053µg/m³
Optical depth1.15
WHO 15
27 Mar29 Mar31 Mar2 Apr
GoodFairModeratePoorVery poorExtremely 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· 11Every satellite heat detection, one by one, with time, satellite, power and coordinates.›
⬇ Download CSVTimes in UTC. Each detection is a 375 m pixel: a large fire yields hundreds per pass.
Copernicus dates it between 29 March 2023 and 31 March 2023: 3 days between the first and last image with fire.
How much area did it burn?
The perimeter Copernicus measured from satellite imagery is 237 hectares (2.4 km²). Official national figures may differ.
Which municipalities burned?
The fire entered 2 municipalities: Tudanca (201 ha, 3.8 %); Cabuérniga (36 ha, 0.4 %).
Did the fire reach a town?
The fire started in Tudanca and came within 1.6 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 22.8 °C, humidity dropped to 25 % and gusts hit 45 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 Spain (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: 25. Their median duration was 2 days and their median area 203 ha; 8 % went past 1,000 ha. All of them had rain in the ten days after the end: the first rainy day brought a median of 3.8 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.
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 errorHow we know this›
Perimeter: EFFIS (Copernicus), mapped on satellite imagery.
Dates from the perimeter: the VIIRS detections inside it did not change them. 11 Suomi-NPP VIIRS detections on those dates.
Compared with EGIF (MITECO): 412 official ha against 237 ha of perimeter; similar, but with reservations.
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 2025, 100 m cells), summed inside the perimeter: an estimate of what was there, not a damage count.
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.