Balsas fire, 4 August 2026 Balsas, Riachão
The fire started on 4 August 2026 in Balsas, Brazil, and satellites saw it burning for 15 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 3,188 hectares from heat detections, spread across 2 municipalities.
It is the 533th largest in Maranhão since 2016 (of 607 with a page). Number 702 in Brazil in 2026, of 757.
Compare with…
Suggestions: Balsas · 2016Balsas · 2021Balsas · 2025Balsas · 2022
- Burnt area
- 3,188ha
- GWIS perimeter (Copernicus)
- Duration
- 15days
- 4 Aug 2026 – 18 Aug 2026
- Municipalities hit
- 2
- municipalities
- Started on
- 4 Aug
- 2026
- Heat detections
- 55
- in a single hotspot: 61 MW
- Danger at start
- 40
- Very high · FWI index
- Average daily power
- 36MW
- detected power per day, on average
Where it burned
How it evolved, day by day
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 19 days without rain (1 mm or more) when it started.
This area had burned before
56% of the perimeter overlaps earlier fires recorded since 2016: 1,490 ha in 2016, 1,380 ha in 2021, 171 ha in 2024. Part of it burned more than once, so the yearly figures add up to more than the 1,780 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
-
3,040 ha reached on 4 Aug0.2 %
-
Riachão 22,145 inhabitants169 ha reached on 10 Aug0.0 %
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 2025Inside 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)
| Day | High | Min. humidity | Peak gust | Rain | Danger (FWI) |
|---|---|---|---|---|---|
| 4 Aug | 33.1 °C | 28 % | 41 km/h | 0.0 mm | Very high 40 |
| 5 Aug | 33.8 °C | 30 % | 37 km/h | 0.0 mm | Very high 38 |
| 6 Aug | 33.9 °C | 31 % | 27 km/h | 0.0 mm | High 35 |
| 7 Aug | 35.1 °C | 29 % | 24 km/h | 0.0 mm | High 34 |
| 8 Aug | 35.1 °C | 32 % | 28 km/h | 0.0 mm | High 36 |
| 9 Aug | 35.6 °C | 28 % | 29 km/h | 0.0 mm | High 37 |
| 10 Aug | 35.7 °C | 27 % | 31 km/h | 0.0 mm | Very high 38 |
| 11 Aug | 33.4 °C | 24 % | 34 km/h | 0.0 mm | Very high 39 |
| 12 Aug | 33.6 °C | 23 % | 44 km/h | 0.0 mm | Very high 45 |
| 13 Aug | 34.1 °C | 28 % | 41 km/h | 0.0 mm | Very high 44 |
| 14 Aug | 35.3 °C | 23 % | 34 km/h | 0.0 mm | Very high 38 |
| 15 Aug | 35.3 °C | 24 % | 39 km/h | 0.0 mm | Very high 43 |
| 16 Aug | 34.7 °C | 21 % | 42 km/h | 0.0 mm | Very high 46 |
| 17 Aug | 33.7 °C | 22 % | 48 km/h | 0.0 mm | Very high 50 |
| 18 Aug | 33.6 °C | 31 % | 42 km/h | 0.0 mm | Very high 44 |
| 19 Aug after | 34.3 °C | 29 % | 41 km/h | 0.0 mm | Very high 44 |
| 20 Aug after | 35.4 °C | 25 % | 35 km/h | 0.0 mm | Very high 41 |
| 21 Aug after | 36.0 °C | 23 % | 35 km/h | 0.0 mm | Very high 42 |
| 22 Aug after | 35.7 °C | 21 % | 34 km/h | 0.0 mm | Very high 43 |
| 23 Aug after | 35.9 °C | 19 % | 34 km/h | 0.0 mm | Very high 47 |
| 24 Aug after | 36.1 °C | 18 % | 32 km/h | 0.0 mm | Very high 45 |
| 25 Aug after | 35.7 °C | 22 % | 37 km/h | 0.0 mm | Very high 47 |
| 26 Aug after | 35.3 °C | 24 % | 44 km/h | 0.0 mm | Extreme 52 |
| 27 Aug after | 34.9 °C | 26 % | 36 km/h | 0.0 mm | Very high 46 |
| 28 Aug after | 36.2 °C | 25 % | 36 km/h | 0.0 mm | Very high 47 |
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 6 August 2026 the air beside the fire reached 21 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 · 55Every satellite heat detection, one by one, with time, satellite, power and coordinates.
| Date and time | Satellite | FRP (MW) | Lat | Lon |
|---|
Other fires nearby
- 12,154 haBalsasSeptember 2021 · 11 days · 11 km away
- 9,484 haBalsas12 October 2025 · 20 days · 18 km away
- 17,378 haBalsas27 September 2022 · 15 days · 26 km away
- 17,385 haBalsas4 August 2022 · 30 days · 28 km away
- 19,217 haBalsas4 October 2025 · 9 days · 30 km away
- 14,958 haBalsas14 September 2025 · 6 days · 37 km away
Frequently asked questions
- How long did the Balsas fire last?
- According to the heat detections seen by satellite inside the perimeter, it burned from 4 August 2026 to 18 August 2026 (15 days). The perimeter dates it from 4 August 2026 to 11 August 2026.
- How much area did it burn?
- The perimeter GWIS (Copernicus) rebuilt from heat detections is 3,188 hectares (31.9 km²). It is an estimate: official national figures may differ.
- Which municipalities burned?
- The fire entered 2 municipalities: Balsas (3,040 ha, 0.2 %); Riachão (169 ha, 0.0 %).
- What was the weather like?
- During the fire the temperature reached 35.7 °C, humidity dropped to 21 % and gusts hit 48 km/h. The fire danger index (FWI) reached 50, class Very high.
- 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.
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: 11 August 2026 → 18 August 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: GWIS (Copernicus), rebuilt from heat detections rather than mapped on imagery.
- Dates adjusted with the VIIRS detections inside the perimeter, which said 4 August 2026 to 11 August 2026. 55 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.