Burned area
satellite only3,679ha
Perimeter published by GWIS (Copernicus).
- Source
- GWIS (Copernicus)
- Date
- 11 Sept 2022 – 20 Sept 2022
+− cross-check
No official record is matched to this page to compare it with.
BR · Brazil · –
Monte Alegre do Piauí fire, 11 September 2022 Monte Alegre do Piauí, Gilbués
Out · last detection 20 Sept 2022, 04:02 UTC
The fire started on 11 September 2022 in Monte Alegre do Piauí, Brazil, and satellites saw it burning for 10 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 3,679 hectares from heat detections, spread across 2 municipalities.
It is the 481th largest in Piaui since 2016 (of 665 with a page). Number 468 in Brazil in 2022, of 682.
Use this data
Compare with…
Use this data
Fire page data · version 2026-10-25matches 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 only10days
11 Sept 2022 to 20 Sept 2022: first and last day with fire on the page.
- Source
- GWIS (Copernicus) · NASA FIRMS · VIIRS
- Date
- last detection: 20 Sept 2022, 04:02 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 only11 Sept 2022
First day with fire seen by the satellites or the perimeter.
- Source
- GWIS (Copernicus) · NASA FIRMS · VIIRS
- Date
- 11 Sept 2022
+− cross-check
No official record is matched to this page, so the alert time and the cause are not known here.
Hotspots
satellite only125
VIIRS detections at 375 m. Most intense hotspot: 108 MW.
- Source
- NASA FIRMS · VIIRS (Suomi NPP)
- Date
- 11 Sept 2022 – 20 Sept 2022
+− 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 only395MW
Total radiative power on 13 September 2022; hotspots that day: 24.
- Source
- NASA FIRMS · VIIRS (FRP)
- Date
- 13 Sept 2022
+− 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
model43.7FWI · very high
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
- 11 Sept 2022, 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
model38.0°C · 18% RH
High of 38.0 °C and minimum humidity of 18% on 15 September 2022; gusts of 38 km/h on 17 September 2022.
- Source
- weather model at the fire’s grid cell
- Date
- 11 Sept 2022 – 20 Sept 2022
- 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 weatherWeather and FWI computed from the ERA5 reanalysis
-
logLast day with fire: 19 September 2022 → 20 September 2022.
-
· reconstructed GHSLPopulation and built-up area computed
What was saved on 25 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
- 3,679 ha
- Dates
- 11 Sept 2022 – 20 Sept 2022
- Name
- Monte Alegre do Piauí
- Official record
- —
Versioned permanent link
https://worldfires.org/en/fire/monte-alegre-do-piaui-2022-09?v=2026-10-25A 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-2022-09.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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 2022-09-11 | 8 | 299 | 37.1 | 18.5 | 17 | 11.4 | 29.9 | 0 | 43.7 | muy_alto | 1 |
| 2022-09-12 | 21 | 258 | 37 | 21.8 | 17 | 15.1 | 34.2 | 0 | 47.9 | muy_alto | 1 |
| 2022-09-13 | 24 | 395 | 36.9 | 18.6 | 18 | 13 | 32 | 0 | 45.9 | muy_alto | 1 |
| 2022-09-14 | 19 | 204 | 37.8 | 18.4 | 16 | 10.4 | 28.8 | 0 | 44.1 | muy_alto | 1 |
| 2022-09-15 | 8 | 36 | 38 | 17.2 | 18 | 11.7 | 29.2 | 0 | 45.7 | muy_alto | 1 |
| 2022-09-16 | 13 | 105 | 36.5 | 20.9 | 23 | 15.2 | 35.3 | 0 | 49 | muy_alto | 1 |
| 2022-09-17 | 17 | 60 | 37 | 20.8 | 19 | 15 | 37.8 | 0 | 49 | muy_alto | 1 |
| 2022-09-18 | 8 | 50 | 36.8 | 20.8 | 20 | 17.6 | 37.8 | 0 | 52.3 | extremo | 1 |
| 2022-09-19 | 6 | 6 | 35.8 | 21.8 | 25 | 15.1 | 36 | 0 | 47.1 | muy_alto | 1 |
| 2022-09-20 | 1 | 1 | 36.6 | 22.2 | 25 | 15.4 | 35.6 | 0 | 47.6 | muy_alto | 1 |
| 2022-09-21 | 0 | 0 | 36.3 | 23.4 | 24 | 12.2 | 32 | 0 | 44.4 | muy_alto | 0 |
| 2022-09-22 | 0 | 0 | 36.7 | 24.9 | 23 | 17.3 | 41 | 0 | 50.3 | extremo | 0 |
| 2022-09-23 | 0 | 0 | 34.8 | 23.1 | 36 | 7.7 | 22 | 0.3 | 33.2 | alto | 0 |
| 2022-09-24 | 0 | 0 | 35.2 | 21.8 | 35 | 13.2 | 30.2 | 2.1 | 20.9 | moderado | 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
- 3,679ha
- GWIS perimeter (Copernicus)
- Duration
- 10days
- 11 Sept 2022 – 20 Sept 2022
- Municipalities hit
- 2
- municipalities
- Started on
- 11 Sept
- 2022
- Heat detections
- 125
- in a single hotspot: 108 MW
- Danger at start
- 44
- Very high · FWI index
- Average daily power
- 141MW
- detected power per day, on average
Where it burned
HOTSPOTS BY DAY
11 Sept20 Sept
20 Sept 2022
How it evolved, day by day
11 Sept
13 Sept
15 Sept
17 Sept
19 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
38km/h · peak gust
16%lowest humidity
It had gone more than two months without rain (1 mm or more) when it started. Rain came after the fire: 2.1 mm on 24 Sept.
This area had burned before
18% of the perimeter overlaps earlier fires recorded since 2016: 671 ha in 2017, 4 ha in 2018.
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
-
3,702 ha reached on 11 Sept1.5 %
-
Gilbués 10,892 inhabitants2 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 2020Built-up area0.29 ha
Residents< 20
Inside the perimeter there were about 0.29 hectares of 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.
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) |
|---|---|---|---|---|---|
| 11 Sept | 37.1 °C | 17 % | 30 km/h | 0.0 mm | Very high 44 |
| 12 Sept | 37.0 °C | 17 % | 34 km/h | 0.0 mm | Very high 48 |
| 13 Sept | 36.9 °C | 18 % | 32 km/h | 0.0 mm | Very high 46 |
| 14 Sept | 37.8 °C | 16 % | 29 km/h | 0.0 mm | Very high 44 |
| 15 Sept | 38.0 °C | 18 % | 29 km/h | 0.0 mm | Very high 46 |
| 16 Sept | 36.5 °C | 23 % | 35 km/h | 0.0 mm | Very high 49 |
| 17 Sept | 37.0 °C | 19 % | 38 km/h | 0.0 mm | Very high 49 |
| 18 Sept | 36.8 °C | 20 % | 38 km/h | 0.0 mm | Extreme 52 |
| 19 Sept | 35.8 °C | 25 % | 36 km/h | 0.0 mm | Very high 47 |
| 20 Sept | 36.6 °C | 25 % | 36 km/h | 0.0 mm | Very high 48 |
| 21 Sept after | 36.3 °C | 24 % | 32 km/h | 0.0 mm | Very high 44 |
| 22 Sept after | 36.7 °C | 23 % | 41 km/h | 0.0 mm | Extreme 50 |
| 23 Sept after | 34.8 °C | 36 % | 22 km/h | 0.3 mm | High 33 |
| 24 Sept after | 35.2 °C | 35 % | 30 km/h | 2.1 mm | Moderate 21 |
Its twins: fires that started in the same weather
It started with an FWI of 43.7, a minimum humidity of 17% and more than two months without rain. Fires in the area that started in weather like this since 2016: 40.
FWI at the start
43.7
Minimum humidity
17 %
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, 11 September 2022
3,679 ha
10 days
FWI 43.7
Min. humidity 17 %
Sebastião Barros fire, September 2025
3,714 ha
8 days
FWI 43.3
Min. humidity 18 %
113 km away, in 2025
First rain (1 mm or more) after it ended: none in the following ten days.
Formosa do Rio Preto fire, October 2020
6,677 ha
6 days
FWI 44.4
Min. humidity 18 %
124 km away, in 2020
First rain (1 mm or more) after it ended: 2.4 mm on 10 Oct.
Gilbués fire, September 2025
3,216 ha
6 days
FWI 44.8
Min. humidity 19 %
60 km away, in 2025
First rain (1 mm or more) after it ended: 23.4 mm on 20 Oct.
Corrente fire, September 2020
9,841 ha
21 days
FWI 42.2
Min. humidity 19 %
58 km away, in 2020
First rain (1 mm or more) after it ended: 7.7 mm on 25 Oct.
Formosa do Rio Preto fire, August 2025
5,340 ha
15 days
FWI 42.7
Min. humidity 16 %
164 km away, in 2025
First rain (1 mm or more) after it ended: none in the following ten days.
What happened to them
- 10 days
- median duration
- 4,756 ha
- median area
- 8 %
- went past 10,000 ha
- 3.2 mm
- rain at the end (median; 22 of 40 had it)
It burned an area similar to its twins (3,679 ha against a median of 4,756 ha) and lasted 10 days, against 10 days.
In 18 of 40, 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 3.2 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
2.1 mmfirst rain
24 Sept4 days after it ended
38km/h · max. gust
It was considered over on 20 Sept, and on 24 Sept 2.1 mm fell. We do not know whether the rain or the firefighters put it out. Twins with rain when they ended: 22 of 40, with a median of 3.2 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 · 4 Sept 2022
After · 27 Sept 2022
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 15 September 2022 the air beside the fire reached 45 µg/m³ of PM2.5. That day averaged 24: 1.6 times the WHO daily guideline (15).
PM2.5 peak45 µg/m³
Days over the guideline1 day
PM1064 µg/m³
Optical depth0.35
WHO 15
9 Sept12 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 · 125Every 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?
- According to the heat detections seen by satellite inside the perimeter, it burned from 11 September 2022 to 20 September 2022 (10 days). The perimeter dates it from 11 September 2022 to 19 September 2022.
- How much area did it burn?
- The perimeter GWIS (Copernicus) rebuilt from heat detections is 3,679 hectares (36.8 km²). It is an estimate: official national figures may differ.
- Which municipalities burned?
- The fire entered 2 municipalities: Monte Alegre do Piauí (3,702 ha, 1.5 %); Gilbués (2 ha, 0.0 %).
- What was the weather like?
- During the fire the temperature reached 38.0 °C, humidity dropped to 16 % and gusts hit 38 km/h. The fire danger index (FWI) reached 52, 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: 40. Their median duration was 10 days and their median area 4,756 ha; 8 % went past 10,000 ha. In 18 of 40, 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 3.2 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 · 1 Changes in area, dates, name, official record or merged pages, compared every night since 24 October 2026.
- Last day with fire: 19 September 2022 → 20 September 2022.
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 adjusted with the VIIRS detections inside the perimeter, which said 11 September 2022 to 19 September 2022. 125 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 2020, 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.