Montemorelos fire, March 2021
Montemorelos, Rayones
Out · last detection 31 Mar 2021, 08:42 UTC
The fire started on 18 March 2021 in Montemorelos, Mexico, and satellites saw it burning for 14 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 5,895 hectares from heat detections, spread across 2 municipalities.
It is the 2th largest in Nuevo León since 2016 (of 16 with a page). Number 35 in Mexico in 2021, of 294.
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
5,895ha
Perimeter published by GWIS (Copernicus).
This page5,895CONAFOR3,518
Source
GWIS (Copernicus)
Date
18 Mar 2021 – 31 Mar 2021
+− cross-check
CONAFOR: 3,518 ha (matched records: 1). Difference between the page and the official record: +67.6%. 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
14days
18 Mar 2021 to 31 Mar 2021: first and last day with fire on the page.
Source
GWIS (Copernicus) · NASA FIRMS · VIIRS
Date
last detection: 31 Mar 2021, 08:42 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
18 Mar 2021
First day with fire seen by the satellites or the perimeter.
Source
GWIS (Copernicus) · NASA FIRMS · VIIRS
Date
18 Mar 2021
+− 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
407
VIIRS detections at 375 m. Most intense hotspot: 91 MW.
Source
NASA FIRMS · VIIRS (Suomi NPP)
Date
18 Mar 2021 – 31 Mar 2021
+− 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
922MW
Total radiative power on 27 March 2021; hotspots that day: 86.
Source
NASA FIRMS · VIIRS (FRP)
Date
27 Mar 2021
+− 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
21.9FWI · high
Fire Weather Index (Canadian system) computed by WorldFires for the day the fire started. Consecutive days without rain before: 16.
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
30.8°C · 20% RH
High of 30.8 °C and minimum humidity of 20% on 27 March 2021; gusts of 49 km/h on 22 March 2021.
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 CONAFOR record
Nearby records with very different figures: 3,518 ha (records: 1).
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
Burnt area inside each municipality, from crossing the GWIS 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.
People and buildings inside the perimeter
GHSL 2020
Built-up area< 0.1ha
Residents< 20
Inside the perimeter there was no noticeable built-up land and almost nobody lived there (GHSL 2020, 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.
According to CONAFOR, this fire started on 18 March 2021 and burned 3,518 ha (the satellite measured 5,895 ha). The two figures differ a lot, so these may not be exactly the same fire: take them as nearby records.
MontemorelosP.P. El Puerto18 March 20213,518 ha· extinguished on 3 April 2021· cause: negligence
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)
18 Mar
21.5 °C
25 %
35 km/h
0.0 mm
High 22
19 Mar
20.2 °C
38 %
36 km/h
0.0 mm
Moderate 19
20 Mar
21.0 °C
44 %
38 km/h
0.0 mm
Moderate 17
21 Mar
23.7 °C
42 %
33 km/h
0.0 mm
Moderate 16
22 Mar
28.1 °C
37 %
49 km/h
0.0 mm
Moderate 16
23 Mar
25.1 °C
35 %
45 km/h
0.4 mm
Moderate 16
24 Mar
28.3 °C
27 %
49 km/h
0.0 mm
Moderate 21
25 Mar
25.2 °C
23 %
41 km/h
0.0 mm
High 22
26 Mar
28.2 °C
24 %
41 km/h
0.0 mm
High 23
27 Mar
30.8 °C
20 %
40 km/h
0.0 mm
High 26
28 Mar
20.0 °C
53 %
42 km/h
12.8 mm
Very low 1
29 Mar
22.6 °C
43 %
37 km/h
2.1 mm
Very low 2
30 Mar
28.0 °C
32 %
28 km/h
0.0 mm
Low 8
31 Mar
26.2 °C
41 %
44 km/h
5.7 mm
Very low 2
1 Apr after
17.4 °C
81 %
27 km/h
6.0 mm
Very low 0
Its twins: fires that started in the same weather
It started with an FWI of 21.9, a minimum humidity of 25% and 16 days without rain. Fires in the area that started in weather like this since 2017: 5.
FWI at the start21.9
Minimum humidity25 %
Days without rain16
this firechosen twinsrest of the area
Almost identicalSimilar
Outlines of the closest twins
This fire · Montemorelos fire, March 2021
5,895 ha14 daysFWI 21.9Min. humidity 25 %
Gómez Farías fire, March 2022
11,127 ha32 daysFWI 20.0Min. humidity 26 %238 km away, in 2022
First rain (1 mm or more) after it ended: 2.6 mm on 19 Apr.
Fires in the area that started in similar weather: 5. With fewer than 15 we give no figures: they would be more noise than signal.
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
6.0 mmfirst rain
1 Aprthe day after it ended
49km/h · max. gust
It was considered over on 31 Mar, and on 1 Apr 6.0 mm fell. We do not know whether the rain or the firefighters put it out.
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 2017.
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.
GWIS (Copernicus) dates it between 18 March 2021 and 31 March 2021: 14 days between the first and last heat detection of the perimeter.
How much area did it burn?
The perimeter GWIS (Copernicus) rebuilt from heat detections is 5,895 hectares (59.0 km²). It is an estimate: official national figures may differ.
Which municipalities burned?
The fire entered 2 municipalities: Montemorelos (4,202 ha, 2.2 %); Rayones (1,716 ha, 2.5 %).
What was the weather like?
During the fire the temperature reached 30.8 °C, humidity dropped to 20 % and gusts hit 49 km/h. The fire danger index (FWI) reached 26, class High.
Where does this data come from?
From the GWIS (Copernicus) burnt perimeter, NASA FIRMS VIIRS hotspots and the administrative boundaries of Mexico (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.
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: GWIS (Copernicus), rebuilt from heat detections rather than mapped on imagery.
Dates from the perimeter: the VIIRS detections inside it did not change them. 407 Suomi-NPP VIIRS detections on those dates.
Compared with CONAFOR: 3,518 official ha against 5,895 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 2020, 100 m cells), summed inside the perimeter: an estimate of what was there, not a damage count.
The perimeter comes from the Copernicus Global Wildfire Information System (GWIS), which rebuilds it from MODIS and VIIRS heat detections and publishes it under CC BY 4.0. It is not measured on imagery as in Europe, so it is an estimate. 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 ADM2 (Creative Commons Attribution 4.0 (CC BY 4.0)). The area per municipality is computed by WorldFires by crossing the perimeter with those boundaries, so it may differ from each country’s official figure.