The fire started on 19 September 2018 in Riacho Frio, Brazil, and satellites saw it burning for 26 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 24,602 hectares from heat detections, spread across 2 municipalities.
It is the 16th largest in Piaui since 2016 (of 665 with a page). Number 4 in Brazil in 2018, of 291.
Union of 2 GWIS (Copernicus) perimeters: overlapping areas count once.
No official record is matched to this page to compare it with.
19 Sept 2018 to 14 Oct 2018: first and last day with fire on the page.
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.
First day with fire seen by the satellites or the perimeter.
No official record is matched to this page, so the alert time and the cause are not known here.
VIIRS detections at 375 m. Most intense hotspot: 554 MW.
There is no official record to compare with. Each hotspot is a pixel detected in one satellite pass, not a separate fire.
Total radiative power on 28 September 2018; hotspots that day: 94.
Fire radiative power (FRP) measures the energy the fire gives off when the satellite passes. Added up by day, it compares intensity, not area.
Fire Weather Index (Canadian system) computed by WorldFires for the day the fire started. Consecutive days without rain before: 12.
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
High of 39.0 °C and minimum humidity of 25% on 4 October 2018; gusts of 42 km/h on 21 September 2018.
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.
Estimated residents inside the perimeter and 6.6 ha of built-up area (100 m grid, epoch 2020).
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.
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.
Every night a snapshot of what the page shows is saved. If anything changes, it appears in the list as a log entry.
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.
| 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 2018-09-19 | 9 | 463 | 38.5 | 25.1 | 21 | 15.9 | 37.1 | 0 | 52.2 | extremo | 1 |
| 2018-09-20 | 34 | 217 | 37.3 | 25.6 | 18 | 18 | 41 | 0 | 58.4 | extremo | 1 |
| 2018-09-21 | 20 | 94 | 37.1 | 24.4 | 23 | 18.4 | 42.1 | 0 | 55.8 | extremo | 1 |
| 2018-09-22 | 9 | 643 | 38.4 | 23.5 | 21 | 14 | 31.3 | 0 | 51.5 | extremo | 1 |
| 2018-09-23 | 37 | 1,403 | 37.6 | 25.4 | 27 | 15.9 | 38.2 | 0 | 54.5 | extremo | 1 |
| 2018-09-24 | 47 | 84 | 35.7 | 26.1 | 34 | 14.5 | 33.5 | 0 | 46.4 | muy_alto | 1 |
| 2018-09-25 | 4 | 7 | 36.3 | 25.6 | 30 | 17.6 | 38.9 | 0 | 50 | extremo | 1 |
| 2018-09-26 | 14 | 129 | 37 | 24.5 | 26 | 17.5 | 39.2 | 0 | 50.2 | extremo | 1 |
| 2018-09-27 | 34 | 1,165 | 37.6 | 24.8 | 26 | 15.4 | 37.1 | 0 | 50.7 | extremo | 1 |
| 2018-09-28 | 94 | 4,064 | 38.5 | 24.5 | 24 | 14.1 | 33.8 | 0 | 50.6 | extremo | 1 |
| 2018-09-29 | 147 | 2,032 | 38.2 | 24.5 | 24 | 10.3 | 22.7 | 0 | 47.5 | muy_alto | 1 |
| 2018-09-30 | 92 | 954 | 37.3 | 24.5 | 29 | 12 | 31 | 0 | 50.5 | extremo | 1 |
| 2018-10-01 | 82 | 910 | 36.5 | 24.6 | 30 | 14 | 33.8 | 0 | 48.4 | muy_alto | 1 |
| 2018-10-02 | 46 | 635 | 37.2 | 23.6 | 25 | 14 | 34.2 | 0 | 48 | muy_alto | 1 |
| 2018-10-03 | 52 | 128 | 37 | 25 | 28 | 13.3 | 33.8 | 0 | 47.2 | muy_alto | 1 |
| 2018-10-04 | 40 | 153 | 39 | 24.5 | 25 | 8.7 | 23.4 | 0 | 46.1 | muy_alto | 1 |
| 2018-10-05 | 35 | 423 | 36.6 | 25.2 | 32 | 12.1 | 30.6 | 0 | 47.7 | muy_alto | 1 |
| 2018-10-06 | 3 | 28 | 35.8 | 25.9 | 33 | 14.6 | 36.4 | 0 | 44.3 | muy_alto | 1 |
| 2018-10-07 | 4 | 42 | 35.9 | 26 | 32 | 15.6 | 37.8 | 0 | 46.7 | muy_alto | 1 |
| 2018-10-08 | 1 | 6 | 37.1 | 25.3 | 26 | 14.4 | 34.9 | 0 | 45.3 | muy_alto | 1 |
| 2018-10-09 | 9 | 106 | 37.2 | 25.4 | 24 | 15.2 | 36 | 0 | 50.5 | extremo | 1 |
| 2018-10-10 | 32 | 878 | 38.3 | 24.6 | 23 | 14.5 | 35.3 | 0 | 49 | muy_alto | 1 |
| 2018-10-11 | 29 | 186 | 38.6 | 24.5 | 22 | 14 | 30.2 | 0 | 49.7 | muy_alto | 1 |
| 2018-10-12 | 6 | 17 | 37.2 | 23.8 | 25 | 16.2 | 29.2 | 0 | 47.3 | muy_alto | 1 |
| 2018-10-13 | 9 | 71 | 37.5 | 24.7 | 25 | 12.3 | 30.2 | 0 | 47 | muy_alto | 1 |
| 2018-10-14 | 2 | 15 | 36.2 | 25.2 | 37 | 10.6 | 25.2 | 0 | 44.9 | muy_alto | 1 |
| 2018-10-15 | 0 | 0 | 36.8 | 25.9 | 35 | 9.5 | 26.6 | 0.2 | 38.6 | muy_alto | 0 |
| 2018-10-16 | 0 | 0 | 29.1 | 23.3 | 66 | 11.7 | 33.1 | 23.6 | 4.2 | muy_bajo | 0 |
It is generated in your browser from this page’s data: one file per fire, aggregated by day and without individual hotspots.
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
Fire radiative power detected each day, in megawatts, and number of hotspots. The magenta bar marks the peak day.
It had gone 12 days without rain (1 mm or more) when it started. Rain came after the fire: 23.6 mm on 16 Oct.
No earlier perimeters overlap this fire since 2016, when the satellite record begins.
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.
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.
Inside the perimeter there were about 6.6 hectares of built-up land and about 200 residents (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
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) |
|---|---|---|---|---|---|
| 19 Sept | 38.5 °C | 21 % | 37 km/h | 0.0 mm | Extreme 52 |
| 20 Sept | 37.3 °C | 18 % | 41 km/h | 0.0 mm | Extreme 58 |
| 21 Sept | 37.1 °C | 23 % | 42 km/h | 0.0 mm | Extreme 56 |
| 22 Sept | 38.4 °C | 21 % | 31 km/h | 0.0 mm | Extreme 52 |
| 23 Sept | 37.6 °C | 27 % | 38 km/h | 0.0 mm | Extreme 54 |
| 24 Sept | 35.7 °C | 34 % | 34 km/h | 0.0 mm | Very high 46 |
| 25 Sept | 36.3 °C | 30 % | 39 km/h | 0.0 mm | Extreme 50 |
| 26 Sept | 37.0 °C | 26 % | 39 km/h | 0.0 mm | Extreme 50 |
| 27 Sept | 37.6 °C | 26 % | 37 km/h | 0.0 mm | Extreme 51 |
| 28 Sept | 38.5 °C | 24 % | 34 km/h | 0.0 mm | Extreme 51 |
| 29 Sept | 38.2 °C | 24 % | 23 km/h | 0.0 mm | Very high 48 |
| 30 Sept | 37.3 °C | 29 % | 31 km/h | 0.0 mm | Extreme 50 |
| 1 Oct | 36.5 °C | 30 % | 34 km/h | 0.0 mm | Very high 48 |
| 2 Oct | 37.2 °C | 25 % | 34 km/h | 0.0 mm | Very high 48 |
| 3 Oct | 37.0 °C | 28 % | 34 km/h | 0.0 mm | Very high 47 |
| 4 Oct | 39.0 °C | 25 % | 23 km/h | 0.0 mm | Very high 46 |
| 5 Oct | 36.6 °C | 32 % | 31 km/h | 0.0 mm | Very high 48 |
| 6 Oct | 35.8 °C | 33 % | 36 km/h | 0.0 mm | Very high 44 |
| 7 Oct | 35.9 °C | 32 % | 38 km/h | 0.0 mm | Very high 47 |
| 8 Oct | 37.1 °C | 26 % | 35 km/h | 0.0 mm | Very high 45 |
| 9 Oct | 37.2 °C | 24 % | 36 km/h | 0.0 mm | Extreme 50 |
| 10 Oct | 38.3 °C | 23 % | 35 km/h | 0.0 mm | Very high 49 |
| 11 Oct | 38.6 °C | 22 % | 30 km/h | 0.0 mm | Very high 50 |
| 12 Oct | 37.2 °C | 25 % | 29 km/h | 0.0 mm | Very high 47 |
| 13 Oct | 37.5 °C | 25 % | 30 km/h | 0.0 mm | Very high 47 |
| 14 Oct | 36.2 °C | 37 % | 25 km/h | 0.0 mm | Very high 45 |
| 15 Oct after | 36.8 °C | 35 % | 27 km/h | 0.2 mm | Very high 39 |
| 16 Oct after | 29.1 °C | 66 % | 33 km/h | 23.6 mm | Very low 4 |
It started with an FWI of 52.2, a minimum humidity of 21% and 12 days without rain. Fires in the area that started in weather like this since 2016: 21.
First rain (1 mm or more) after it ended: 1.1 mm on 26 Sept.
First rain (1 mm or more) after it ended: 6.3 mm on 24 Oct.
First rain (1 mm or more) after it ended: 4.0 mm on 24 Oct.
First rain (1 mm or more) after it ended: 5.8 mm on 21 Oct.
First rain (1 mm or more) after it ended: none in the following ten days.
It was 3.2 times larger than the median of its twins and lasted 26 days, against 13 days.
Only 2 of its 21 twins burned more. The weather on the first day does not explain everything: the wind in the following days, the fuel and the firefighting also count. In 10 of 21, 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 2.5 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
It was considered over on 14 Oct, and on 16 Oct 23.6 mm fell. We do not know whether the rain or the firefighters put it out. Twins with rain when they ended: 11 of 21, with a median of 2.5 mm.
Weather on this page: Open-Meteo.com (CC BY 4.0) · Copernicus Climate Change Service (ERA5)
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.
| Date and time | Satellite | FRP (MW) | Lat | Lon |
|---|
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
No changes since 24 October 2026.
RSS Changes to this page With cross-checks and a citable version
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.
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.