Burned area
satellite only3,776ha
Perimeter published by GWIS (Copernicus).
- Source
- GWIS (Copernicus)
- Date
- 14 Sept 2024 – 20 Sept 2024
+− cross-check
No official record is matched to this page to compare it with.
BR · Brazil · –
Monte Alegre do Piauí fire, September 2024 Bom Jesus, Monte Alegre do Piauí, Gilbués
Out · last detection 20 Sept 2024, 16:31 UTC
The fire started on 14 September 2024 in Monte Alegre do Piauí, Brazil, and satellites saw it burning for 7 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 3,776 hectares from heat detections, spread across 3 municipalities.
It is the 455th largest in Piaui since 2016 (of 665 with a page). Number 977 in Brazil in 2024, of 1301.
Use this data
Compare with…
Use this data
Fire page data · version 2026-10-24matches the official recordwith caveatssatellite onlymodel
When copying, the sentence is
Tick the figures you want: they make up the lede and the CSV.
Duration by satellite
satellite only7days
14 Sept 2024 to 20 Sept 2024: first and last day with fire on the page.
- Source
- GWIS (Copernicus) · NASA FIRMS · VIIRS
- Date
- last detection: 20 Sept 2024, 16:31 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 only14 Sept 2024
First day with fire seen by the satellites or the perimeter.
- Source
- GWIS (Copernicus) · NASA FIRMS · VIIRS
- Date
- 14 Sept 2024
+− cross-check
No official record is matched to this page, so the alert time and the cause are not known here.
Hotspots
satellite only123
VIIRS detections at 375 m. Most intense hotspot: 67 MW.
- Source
- NASA FIRMS · VIIRS (Suomi NPP)
- Date
- 14 Sept 2024 – 20 Sept 2024
+− 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 only594MW
Total radiative power on 17 September 2024; hotspots that day: 21.
- Source
- NASA FIRMS · VIIRS (FRP)
- Date
- 17 Sept 2024
+− 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
model51.7FWI · extreme
Fire Weather Index (Canadian system) computed by WorldFires for the day the fire started. Consecutive days without rain before: 60.
- Source
- WorldFires calculation (Canadian FWI system)
- Date
- 14 Sept 2024, local noon
- Model
- ERA5 0,25° (ECMWF · Copernicus C3S) · Open-Meteo.com
+− cross-check
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
model37.7°C · 16% RH
High of 37.7 °C and minimum humidity of 16% on 17 September 2024; gusts of 46 km/h on 18 September 2024.
- Source
- weather model at the fire’s grid cell
- Date
- 14 Sept 2024 – 20 Sept 2024
- Model
- ERA5 0,25° (ECMWF · Copernicus C3S) · Open-Meteo.com
+− cross-check
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
-
· reconstructed GHSLPopulation and built-up area computed
-
· reconstructed weatherWeather and FWI computed from the ERA5 reanalysis
What was saved on 24 October 2026
Every night a snapshot of what the page shows is saved. If anything changes, it appears in the list as a log entry.
- Area
- 3,776 ha
- Dates
- 14 Sept 2024 – 20 Sept 2024
- Name
- Monte Alegre do Piauí
- Official record
- —
Versioned permanent link
https://worldfires.org/en/fire/monte-alegre-do-piaui-2024-09?v=2026-10-24A 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 monte-alegre-do-piaui-2024-09.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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 2024-09-14 | 3 | 13 | 34.6 | 21 | 19 | 17.3 | 38.9 | 0 | 51.7 | extremo | 1 |
| 2024-09-15 | 5 | 49 | 35.9 | 19.8 | 21 | 16.6 | 38.5 | 0 | 51.2 | extremo | 1 |
| 2024-09-16 | 10 | 136 | 36.4 | 22.5 | 22 | 16 | 37.1 | 0 | 50.7 | extremo | 1 |
| 2024-09-17 | 21 | 594 | 37.7 | 22.1 | 16 | 15.7 | 37.1 | 0 | 50.6 | extremo | 1 |
| 2024-09-18 | 45 | 290 | 36.9 | 23.8 | 16 | 19.7 | 45.7 | 0 | 55.7 | extremo | 1 |
| 2024-09-19 | 33 | 280 | 35.7 | 21 | 19 | 18.9 | 42.5 | 0 | 54.9 | extremo | 1 |
| 2024-09-20 | 6 | 32 | 36.7 | 21.4 | 17 | 17.3 | 40 | 0 | 53.2 | extremo | 1 |
| 2024-09-21 | 0 | 0 | 37.3 | 22.5 | 17 | 16.1 | 37.1 | 0 | 52 | extremo | 0 |
| 2024-09-22 | 0 | 0 | 37.3 | 21.9 | 18 | 17 | 40.7 | 0 | 53.3 | extremo | 0 |
| 2024-09-23 | 0 | 0 | 37.1 | 21.8 | 19 | 17.2 | 39.6 | 0 | 53.8 | extremo | 0 |
| 2024-09-24 | 0 | 0 | 36.7 | 22.7 | 20 | 15.7 | 37.8 | 0 | 52.2 | extremo | 0 |
| 2024-09-25 | 0 | 0 | 34 | 25.3 | 29 | 17.1 | 38.9 | 0 | 46 | muy_alto | 0 |
| 2024-09-26 | 0 | 0 | 35.4 | 24.6 | 23 | 17.5 | 40.7 | 0 | 46.6 | muy_alto | 0 |
| 2024-09-27 | 0 | 0 | 36.5 | 22.9 | 20 | 17.4 | 40 | 0 | 47.8 | muy_alto | 0 |
| 2024-09-28 | 0 | 0 | 38.7 | 21.7 | 17 | 13.9 | 33.8 | 0 | 48 | muy_alto | 0 |
| 2024-09-29 | 0 | 0 | 36 | 24.5 | 25 | 16.7 | 37.1 | 0 | 49.2 | muy_alto | 0 |
| 2024-09-30 | 0 | 0 | 34.9 | 23.7 | 28 | 19.6 | 43.6 | 0 | 49.4 | muy_alto | 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: GWIS (Copernicus), NASA FIRMS (VIIRS), ERA5 (ECMWF/Copernicus C3S) · Open-Meteo.com (CC BY 4.0), GHSL (JRC). Open-Meteo.com · How we build fire pages: methodology
- Burnt area
- 3,776ha
- GWIS perimeter (Copernicus)
- Duration
- 7days
- 14 Sept 2024 – 20 Sept 2024
- Municipalities hit
- 3
- municipalities
- Started on
- 14 Sept
- 2024
- Heat detections
- 123
- in a single hotspot: 67 MW
- Danger at start
- 52
- Extreme · FWI index
- Average daily power
- 199MW
- detected power per day, on average
Where it burned
HOTSPOTS BY DAY
14 Sept20 Sept
20 Sept 2024
How it evolved, day by day
14 Sept
17 Sept
20 Sept
Fire radiative power detected each day, in megawatts, and number of hotspots. The magenta bar marks the peak day.
The weather it burned in
38°high
46km/h · peak gust
16%lowest humidity
It had gone more than two months without rain (1 mm or more) when it started.
This area had burned before
72% of the perimeter overlaps earlier fires recorded since 2016: 397 ha in 2016, 415 ha in 2018, 1,698 ha in 2020, 911 ha in 2022, 1,083 ha in 2023. Part of it burned more than once, so the yearly figures add up to more than the 2,709 ha that had burned before.
How big is it?
London boundary: geoBoundaries · Office for National Statistics (Open Government Licence v3.0).
Paris boundary: geoBoundaries · Institut national de l'information géographique et forestière (IGN-F) (Etalab Open License 2.0).
Madrid boundary: geoBoundaries · Open Data ESRI, IGN Central Registry of Cartography Area (CC BY 4.0).
Berlin boundary: geoBoundaries · Federal Agency for Cartography and Geodesy (dl-de/by-2-0).
This compares size, not location: both shapes are at the same scale, north up, centred on each other.
What happened to each town
-
Bom Jesus 28,796 inhabitants2,056 ha reached on 17 Sept0.4 %
-
1,732 ha reached on 14 Sept0.7 %
-
Gilbués 10,892 inhabitants12 ha0.0 %
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 2025Built-up area< 0.1 ha
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.
Source: Global Human Settlement Layer (GHS-BUILT-S and GHS-POP R2023A), European Commission Joint Research Centre (JRC), © European Union, CC BY 4.0. Sum inside the perimeter computed by WorldFires. human-settlement.emergency.copernicus.eu
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)
Started with 60 days without rain: 55 % of the area in Brazil
| Day | High | Min. humidity | Peak gust | Rain | Danger (FWI) |
|---|---|---|---|---|---|
| 14 Sept | 34.6 °C | 19 % | 39 km/h | 0.0 mm | Extreme 52 |
| 15 Sept | 35.9 °C | 21 % | 38 km/h | 0.0 mm | Extreme 51 |
| 16 Sept | 36.4 °C | 22 % | 37 km/h | 0.0 mm | Extreme 51 |
| 17 Sept | 37.7 °C | 16 % | 37 km/h | 0.0 mm | Extreme 51 |
| 18 Sept | 36.9 °C | 16 % | 46 km/h | 0.0 mm | Extreme 56 |
| 19 Sept | 35.7 °C | 19 % | 42 km/h | 0.0 mm | Extreme 55 |
| 20 Sept | 36.7 °C | 17 % | 40 km/h | 0.0 mm | Extreme 53 |
| 21 Sept after | 37.3 °C | 17 % | 37 km/h | 0.0 mm | Extreme 52 |
| 22 Sept after | 37.3 °C | 18 % | 41 km/h | 0.0 mm | Extreme 53 |
| 23 Sept after | 37.1 °C | 19 % | 40 km/h | 0.0 mm | Extreme 54 |
| 24 Sept after | 36.7 °C | 20 % | 38 km/h | 0.0 mm | Extreme 52 |
| 25 Sept after | 34.0 °C | 29 % | 39 km/h | 0.0 mm | Very high 46 |
| 26 Sept after | 35.4 °C | 23 % | 41 km/h | 0.0 mm | Very high 47 |
| 27 Sept after | 36.5 °C | 20 % | 40 km/h | 0.0 mm | Very high 48 |
| 28 Sept after | 38.7 °C | 17 % | 34 km/h | 0.0 mm | Very high 48 |
| 29 Sept after | 36.0 °C | 25 % | 37 km/h | 0.0 mm | Very high 49 |
| 30 Sept after | 34.9 °C | 28 % | 44 km/h | 0.0 mm | Very high 49 |
Its twins: fires that started in the same weather
It started with an FWI of 51.7, a minimum humidity of 19% and more than two months without rain. Fires in the area that started in weather like this since 2016: 18.
FWI at the start
51.7
Minimum humidity
19 %
Days without rain
60+
this fire
chosen twins
rest of the area
Almost identicalSimilar
Outlines of the closest twins
This fire · Monte Alegre do Piauí fire, September 2024
3,776 ha
7 days
FWI 51.7
Min. humidity 19 %
Monte Alegre do Piauí fire, October 2020
4,511 ha
11 days
FWI 51.9
Min. humidity 20 %
41 km away, in 2020
First rain (1 mm or more) after it ended: 1.0 mm on 25 Oct.
Baixa Grande do Ribeiro fire, September 2025
3,009 ha
4 days
FWI 52.5
Min. humidity 20 %
28 km away, in 2025
First rain (1 mm or more) after it ended: none in the following ten days.
Baixa Grande do Ribeiro fire, August 2025
4,765 ha
13 days
FWI 53.1
Min. humidity 18 %
50 km away, in 2025
First rain (1 mm or more) after it ended: none in the following ten days.
Bom Jesus fire, September 2025
4,159 ha
10 days
FWI 53.2
Min. humidity 20 %
53 km away, in 2025
First rain (1 mm or more) after it ended: none in the following ten days.
Riacho Frio fire, August 2022
4,715 ha
17 days
FWI 52.1
Min. humidity 21 %
52 km away, in 2022
First rain (1 mm or more) after it ended: none in the following ten days.
What happened to them
- 9 days
- median duration
- 3,785 ha
- median area
- 0 %
- went past 10,000 ha
- 2.2 mm
- rain at the end (median; 7 of 18 had it)
It burned an area similar to its twins (3,776 ha against a median of 3,785 ha) and lasted 7 days, against 9 days.
In 11 of 18, not even 1 mm fell in the ten days after the end: they went out without rain. In the rest, the first rainy day brought a median of 2.2 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
—first rain
—no rain in ten days
46km/h · max. gust
It was considered over on 20 Sept, and not even 1 mm fell in the following ten days: it went out without rain. Twins with rain when they ended: 7 of 18, with a median of 2.2 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.
Before and after, from space
Drag the line to compare the same ground before the fire and after it.
↔
Before · 7 Sept 2024
After · 27 Sept 2024
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 · CopernicusOn 17 September 2024 the air beside the fire reached 12 µg/m³ of PM2.5, but no daily average passed the WHO guideline (15).
PM2.5 peak12 µg/m³
Days over the guideline0 days
PM1017 µg/m³
Optical depth0.34
12 Sept15 Sept18 Sept21 Sept
Good
Fair
Moderate
Poor
Very poor
Extremely 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 · 123Every satellite heat detection, one by one, with time, satellite, power and coordinates.
⬇ Download CSV
Times in UTC. Each detection is a 375 m pixel: a large fire yields hundreds per pass.
| Date and time | Satellite | FRP (MW) | Lat | Lon |
|---|
Other fires nearby
Frequently asked questions
- How long did the Monte Alegre do Piauí fire last?
- GWIS (Copernicus) dates it between 14 September 2024 and 20 September 2024: 7 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 3,776 hectares (37.8 km²). It is an estimate: official national figures may differ.
- Which municipalities burned?
- The fire entered 3 municipalities: Bom Jesus (2,056 ha, 0.4 %); Monte Alegre do Piauí (1,732 ha, 0.7 %); Gilbués (12 ha, 0.0 %).
- What was the weather like?
- During the fire the temperature reached 37.7 °C, humidity dropped to 16 % and gusts hit 46 km/h. The fire danger index (FWI) reached 56, class Extreme.
- Where does this data come from?
- From the GWIS (Copernicus) burnt perimeter, NASA FIRMS VIIRS hotspots and the administrative boundaries of Brazil (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: 18. Their median duration was 9 days and their median area 3,785 ha; 0 % went past 10,000 ha. In 11 of 18, not even 1 mm fell in the ten days after the end: they went out without rain. In the rest, the first rainy day brought a median of 2.2 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.
Emergency number: 193 · 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.
RSS Changes to this page With cross-checks and a citable version
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: GWIS (Copernicus), rebuilt from heat detections rather than mapped on imagery.
- Dates from the perimeter: the VIIRS detections inside it did not change them. 123 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.
- 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.
Where this data comes from
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 3.0 Intergovernmental Organisations (CC BY 3.0 IGO)). 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.