Loreto fire, August 2021 Loreto, Sambaíba
The fire started on 5 August 2021 in Loreto, Brazil, and satellites saw it burning for 6 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 3,742 hectares from heat detections, spread across 2 municipalities.
It is the 394th largest in Maranhão since 2016 (of 607 with a page). Number 604 in Brazil in 2021, of 814.
Compare with…
- Burnt area
- 3,742ha
- GWIS perimeter (Copernicus)
- Duration
- 6days
- 5 Aug 2021 – 10 Aug 2021
- Municipalities hit
- 2
- municipalities
- Started on
- 5 Aug
- 2021
- Heat detections
- 129
- in a single hotspot: 38 MW
- Danger at start
- 40
- Very high · FWI index
- Average daily power
- 117MW
- 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 more than two months without rain (1 mm or more) when it started.
This area had burned before
68% of the perimeter overlaps earlier fires recorded since 2016: 1,184 ha in 2017, 683 ha in 2018, 2,043 ha in 2019. Part of it burned more than once, so the yearly figures add up to more than the 2,558 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
-
3,767 ha reached on 31 Jul1.0 %
-
Sambaíba 5,568 inhabitants0 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 2020Inside the perimeter there were about 0.20 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)
| Day | High | Min. humidity | Peak gust | Rain | Danger (FWI) |
|---|---|---|---|---|---|
| 31 Jul | 33.2 °C | 36 % | 42 km/h | 0.0 mm | Very high 40 |
| 1 Aug | 32.8 °C | 37 % | 53 km/h | 0.0 mm | Very high 45 |
| 2 Aug | 33.0 °C | 31 % | 42 km/h | 0.0 mm | Very high 39 |
| 3 Aug | 34.1 °C | 32 % | 33 km/h | 0.0 mm | High 35 |
| 4 Aug | 34.5 °C | 30 % | 35 km/h | 0.0 mm | High 37 |
| 5 Aug | 34.1 °C | 27 % | 36 km/h | 0.0 mm | Very high 39 |
| 6 Aug | 34.7 °C | 31 % | 42 km/h | 0.0 mm | Very high 41 |
| 7 Aug | 33.9 °C | 31 % | 46 km/h | 0.0 mm | Very high 45 |
| 8 Aug | 34.4 °C | 30 % | 43 km/h | 0.0 mm | Very high 43 |
| 9 Aug | 35.1 °C | 26 % | 36 km/h | 0.0 mm | Very high 40 |
| 10 Aug | 35.8 °C | 31 % | 38 km/h | 0.0 mm | Very high 41 |
| 11 Aug after | 36.2 °C | 32 % | 34 km/h | 0.0 mm | Very high 40 |
| 12 Aug after | 37.1 °C | 29 % | 32 km/h | 0.0 mm | Very high 39 |
| 13 Aug after | 35.1 °C | 32 % | 37 km/h | 0.0 mm | Very high 42 |
| 14 Aug after | 35.2 °C | 28 % | 31 km/h | 0.0 mm | Very high 41 |
| 15 Aug after | 35.4 °C | 25 % | 30 km/h | 0.0 mm | Very high 39 |
| 16 Aug after | 34.8 °C | 29 % | 28 km/h | 0.0 mm | Very high 38 |
| 17 Aug after | 36.0 °C | 22 % | 34 km/h | 0.0 mm | Very high 43 |
| 18 Aug after | 35.3 °C | 23 % | 38 km/h | 0.0 mm | Very high 45 |
| 19 Aug after | 33.9 °C | 28 % | 43 km/h | 0.0 mm | Very high 48 |
| 20 Aug after | 34.5 °C | 28 % | 40 km/h | 0.0 mm | Very high 46 |
| 21 Aug after | 34.9 °C | 30 % | 40 km/h | 0.0 mm | Very high 46 |
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.
Detections table · 129Every satellite heat detection, one by one, with time, satellite, power and coordinates.
| Date and time | Satellite | FRP (MW) | Lat | Lon |
|---|
Other fires nearby
Frequently asked questions
- How long did the Loreto fire last?
- GWIS (Copernicus) dates it between 5 August 2021 and 10 August 2021: 6 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 3,742 hectares (37.4 km²). It is an estimate: official national figures may differ.
- Which municipalities burned?
- The fire entered 2 municipalities: Loreto (3,767 ha, 1.0 %); Sambaíba (0 ha, 0.0 %).
- What was the weather like?
- During the fire the temperature reached 36.2 °C, humidity dropped to 26 % and gusts hit 53 km/h. The fire danger index (FWI) reached 45, 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 Changes in area, dates, name, official record or merged pages, compared every night since 24 October 2026.
No changes since 24 October 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 from the perimeter: the VIIRS detections inside it did not change them. 129 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.