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BR · Brazil · –

Francisco Ayres fire, August 2019 Francisco Ayres, Floriano, Amarante

Out · last detection 11 Sept 2019, 16:57 UTC

The fire started on 6 August 2019 in Francisco Ayres, Brazil, and satellites saw it burning for 36 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 13,813 hectares from heat detections, spread across 3 municipalities.

It is the 52th largest in Piaui since 2016 (of 665 with a page). Number 99 in Brazil in 2019, of 973.

Burnt area
13,813ha
GWIS perimeter (Copernicus)
Duration
36days
6 Aug 2019 – 10 Sept 2019
Municipalities hit
3
municipalities
Started on
6 Aug
2019
Heat detections
871
in a single hotspot: 49 MW
Danger at start
62
Extreme · FWI index
Average daily power
131MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 6 Aug10 Sept
11 Sept 2019

How it evolved, day by day

6 Aug 2019 · 31 MW · 5 7 Aug 2019 · 15 MW · 5 10 Aug 2019 · 3 MW · 2 13 Aug 2019 · 8 MW · 3 14 Aug 2019 · 13 MW · 7 15 Aug 2019 · 23 MW · 9 16 Aug 2019 · 91 MW · 21 17 Aug 2019 · 62 MW · 13 18 Aug 2019 · 58 MW · 10 19 Aug 2019 · 115 MW · 20 20 Aug 2019 · 89 MW · 26 21 Aug 2019 · 399 MW · 61 22 Aug 2019 · 339 MW · 46 23 Aug 2019 · 159 MW · 31 24 Aug 2019 · 84 MW · 16 25 Aug 2019 · 68 MW · 13 26 Aug 2019 · 257 MW · 63 27 Aug 2019 · 444 MW · 73 28 Aug 2019 · 455 MW · 61 29 Aug 2019 · 476 MW · 88 30 Aug 2019 · 238 MW · 65 31 Aug 2019 · 139 MW · 50 1 Sept 2019 · 130 MW · 34 2 Sept 2019 · 176 MW · 50 3 Sept 2019 · 89 MW · 16 4 Sept 2019 · 43 MW · 9 5 Sept 2019 · 37 MW · 9 6 Sept 2019 · 85 MW · 26 7 Sept 2019 · 99 MW · 14 8 Sept 2019 · 55 MW · 13 9 Sept 2019 · 44 MW · 8 10 Sept 2019 · 6 MW · 2 11 Sept 2019 · 4 MW · 2
6 Aug 17 Aug 24 Aug 29 Aug 7 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

37°high
55km/h · peak gust
23%lowest humidity

It had gone 48 days without rain (1 mm or more) when it started.

This area had burned before

4% of the perimeter overlaps earlier fires recorded since 2016: 606 ha in 2018.

How big is it?

10 km
It burned the equivalent of 8.7% of the area of London (138 km² against 1,583 km²).

London boundary: geoBoundaries · Office for National Statistics (Open Government Licence v3.0).

This compares size, not location: both shapes are at the same scale, north up, centred on each other.

What happened to each town

  1. Francisco Ayres 4,412 inhabitants where it started
    10,950 ha reached on 6 Aug
    17 %
  2. Floriano 62,036 inhabitants
    2,423 ha reached on 6 Aug
    0.7 %
  3. Amarante 17,234 inhabitants
    529 ha reached on 13 Aug
    0.4 %

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 2020
Built-up area2.0 ha
Residents≈ 80

Inside the perimeter there were about 2.0 hectares of built-up land and about 80 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

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 Extreme FWI: 46 % of the area in Brazil Strong wind: 3.1 % of the area in Brazil

Day High Min. humidity Peak gust Rain Danger (FWI)
6 Aug 31.9 °C 36 % 55 km/h 0.0 mm Extreme 62
7 Aug 34.8 °C 33 % 51 km/h 0.0 mm Extreme 54
8 Aug 33.5 °C 34 % 50 km/h 0.0 mm Extreme 52
9 Aug 34.9 °C 23 % 46 km/h 0.0 mm Extreme 51
10 Aug 34.6 °C 27 % 47 km/h 0.0 mm Extreme 56
11 Aug 35.5 °C 28 % 44 km/h 0.0 mm Extreme 54
12 Aug 35.2 °C 29 % 44 km/h 0.0 mm Extreme 54
13 Aug 35.1 °C 31 % 50 km/h 0.0 mm Extreme 54
14 Aug 35.5 °C 30 % 44 km/h 0.0 mm Extreme 51
15 Aug 35.1 °C 32 % 49 km/h 0.0 mm Extreme 62
16 Aug 34.5 °C 24 % 53 km/h 0.0 mm Extreme 63
17 Aug 33.8 °C 37 % 52 km/h 0.0 mm Extreme 63
18 Aug 35.2 °C 33 % 44 km/h 0.0 mm Extreme 51
19 Aug 36.1 °C 28 % 41 km/h 0.0 mm Very high 49
20 Aug 37.0 °C 32 % 35 km/h 0.0 mm Very high 43
21 Aug 36.8 °C 29 % 33 km/h 0.0 mm Very high 42
22 Aug 37.0 °C 26 % 38 km/h 0.0 mm Extreme 50
23 Aug 35.3 °C 26 % 44 km/h 0.0 mm Extreme 56
24 Aug 35.6 °C 28 % 37 km/h 0.0 mm Very high 48
25 Aug 36.0 °C 24 % 43 km/h 0.0 mm Extreme 60
26 Aug 35.1 °C 29 % 48 km/h 0.0 mm Extreme 62
27 Aug 35.7 °C 29 % 50 km/h 0.0 mm Extreme 59
28 Aug 35.3 °C 27 % 46 km/h 0.0 mm Extreme 59
29 Aug 35.8 °C 26 % 48 km/h 0.0 mm Extreme 60
30 Aug 35.8 °C 31 % 44 km/h 0.0 mm Extreme 54
31 Aug 35.8 °C 31 % 42 km/h 0.0 mm Extreme 54
1 Sept 36.2 °C 27 % 39 km/h 0.0 mm Very high 49
2 Sept 36.9 °C 28 % 35 km/h 0.0 mm Very high 46
3 Sept 36.8 °C 30 % 37 km/h 0.0 mm Extreme 52
4 Sept 36.9 °C 30 % 43 km/h 0.0 mm Extreme 54
5 Sept 36.8 °C 30 % 41 km/h 0.0 mm Very high 47
6 Sept 36.5 °C 26 % 45 km/h 0.0 mm Extreme 55
7 Sept 35.4 °C 28 % 50 km/h 0.0 mm Extreme 62
8 Sept 36.1 °C 25 % 49 km/h 0.0 mm Extreme 62
9 Sept 36.2 °C 26 % 49 km/h 0.0 mm Extreme 64
10 Sept 36.1 °C 30 % 50 km/h 0.0 mm Extreme 59
11 Sept after 37.4 °C 23 % 44 km/h 0.0 mm Extreme 56
12 Sept after 37.3 °C 29 % 47 km/h 0.0 mm Extreme 56
13 Sept after 38.1 °C 26 % 41 km/h 0.0 mm Extreme 54
14 Sept after 37.8 °C 27 % 31 km/h 0.0 mm Very high 43
15 Sept after 37.1 °C 21 % 37 km/h 0.0 mm Extreme 54
16 Sept after 37.1 °C 27 % 46 km/h 0.0 mm Extreme 59
17 Sept after 36.6 °C 27 % 45 km/h 0.0 mm Extreme 57
18 Sept after 36.8 °C 31 % 37 km/h 0.0 mm Extreme 52
19 Sept after 38.3 °C 26 % 40 km/h 0.0 mm Extreme 56
20 Sept after 38.4 °C 18 % 43 km/h 0.0 mm Extreme 59

Its twins: fires that started in the same weather

It started with an FWI of 62.3, a minimum humidity of 36% and 48 days without rain. Fires in the area that started in weather like this since 2016: 63.

FWI at the start 62.3
Minimum humidity 36 %
Days without rain 48
this fire chosen twins rest of the area
Almost identicalSimilar

Outlines of the closest twins

Floriano fire, August 2018
4,090 ha 11 days FWI 62.1 Min. humidity 30 % 62 km away, in 2018

First rain (1 mm or more) after it ended: 2.0 mm on 6 Sept.

What happened to them

14 days
median duration
4,090 ha
median area
6 %
went past 10,000 ha
2.0 mm
rain at the end (median; 16 of 63 had it)

It was 3.4 times larger than the median of its twins and lasted 36 days, against 14 days.

Only 4 of its 63 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 47 of 63, 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 2.0 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
55km/h · max. gust

It was considered over on 10 Sept, and not even 1 mm fell in the following ten days: it went out without rain. Twins with rain when they ended: 16 of 63, with a median of 2.0 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.

How we calculate it

Before and after, from space

Drag the line to compare the same ground before the fire and after it.

Before · 30 Jul 2019
After · 17 Sept 2019

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 · 871Every 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 timeSatelliteFRP (MW)LatLon

Other fires nearby

All fires in Brazil

Frequently asked questions

How long did the Francisco Ayres fire last?
According to the heat detections seen by satellite inside the perimeter, it burned from 6 August 2019 to 10 September 2019 (36 days). The perimeter dates it from 13 August 2019 to 8 September 2019.
How much area did it burn?
The perimeter GWIS (Copernicus) rebuilt from heat detections is 13,813 hectares (138.1 km²). It is an estimate: official national figures may differ.
Which municipalities burned?
The fire entered 3 municipalities: Francisco Ayres (10,950 ha, 17 %); Floriano (2,423 ha, 0.7 %); Amarante (529 ha, 0.4 %).
What was the weather like?
During the fire the temperature reached 37.0 °C, humidity dropped to 23 % and gusts hit 55 km/h. The fire danger index (FWI) reached 64, 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: 63. Their median duration was 14 days and their median area 4,090 ha; 6 % went past 10,000 ha. Only 4 of its 63 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 47 of 63, 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 2.0 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 · 2 Changes in area, dates, name, official record or merged pages, compared every night since 24 October 2026.
  1. Last day with fire: 8 September 2019 → 10 September 2019.
  2. Start date: 13 August 2019 → 6 August 2019.

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
What do you think is wrong?

We will only use your email to reply about this report. Privacy. This is not an emergency service: if there is a fire now, call 193.

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 13 August 2019 to 8 September 2019. 871 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.

How we build fire pages: methodology

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.