How long did the Bronco Fire last?

The official perimeter only gives the start date (3 August 2025). The end comes from the heat detections inside the perimeter: it burned until 11 August 2025 (9 days from 3 August 2025), the last day with detections before more than 10 days in a row without any, so it is approximate.

How much area did it burn?

The official perimeter published by United States agencies (MTBS / NIFC) is 7,301 hectares (73.0 km²). Other tallies, such as daily incident reports, may give slightly different figures.

Which counties burned?

The fire only entered Gila (7,328 ha, 0.6 %).

What was the weather like?

During the fire the temperature reached 37.0 °C, humidity dropped to 4 % and gusts hit 47 km/h. The fire danger index (FWI) reached 55, class Extreme.

Where does this data come from?

From the official burnt perimeter of United States agencies (MTBS / NIFC, public domain), NASA FIRMS VIIRS hotspots and the administrative boundaries of United States. It is not an official report.

US · United States · 2025-08-03 → 2025-08-11

Bronco Fire, August 2025 Gila

Out · last detection 11 Aug 2025, 20:14 UTC

The fire started on 3 August 2025 in Gila, United States, and satellites saw it burning for 9 days. United States agencies (MTBS / NIFC) mapped an official burnt perimeter of 7,301 hectares, spread across a single county.

It is the 43th largest in Arizona since 2016 (of 380 with a page). Number 56 in United States in 2025, of 327.

Compare with…

Suggestions: Hilltop · 2017 Cassadore Springs · 2020 Blue River 2 · 2020 Blue River · 2020

Burnt area: 7,301ha; official perimeter (MTBS / NIFC)
Duration: ≈ 9days; 3 Aug 2025 – 11 Aug 2025
Counties hit: 1; counties
Started on: 3 Aug; 2025
Heat detections: 851; in a single hotspot: 608 MW
Danger at start: 55; Extreme · FWI index
Average daily power: 2.4GW; detected power per day, on average

HOTSPOTS BY DAY 3 Aug11 Aug

Play back 11 Aug 2025

How it evolved, day by day

3 Aug 5 Aug 7 Aug 9 Aug 11 Aug

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

47km/h · peak gust

4%lowest humidity

It had gone 3 days without rain (1 mm or more) when it started. Rain came after the fire: 1.0 mm on 12 Aug.

This area had burned before

0% of the perimeter overlaps earlier fires recorded since 2016: 18 ha in 2017.

18 ha Hilltop fire, June 2017 13,340 ha in total; the hectares shown are those it shares with this fire

How big is it?

It burned the equivalent of 4.6% of the area of London (73 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 county

Gila where it started

7,328 ha reached on 3 Aug

0.6 %

Burnt area inside each county, from crossing the official 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.

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)
3 Aug	34.2 °C	4 %	47 km/h	0.0 mm	Extreme 55
4 Aug	34.2 °C	9 %	43 km/h	0.0 mm	Extreme 54
5 Aug	35.2 °C	13 %	39 km/h	0.0 mm	Extreme 55
6 Aug	37.0 °C	11 %	38 km/h	1.1 mm	Very high 47
7 Aug	36.8 °C	9 %	38 km/h	0.0 mm	Extreme 50
8 Aug	35.7 °C	10 %	36 km/h	0.0 mm	Extreme 53
9 Aug	34.4 °C	13 %	37 km/h	1.6 mm	Very high 43
10 Aug	31.2 °C	21 %	38 km/h	1.2 mm	High 32
11 Aug	32.9 °C	16 %	43 km/h	0.2 mm	Very high 46
12 Aug after	32.9 °C	16 %	38 km/h	1.0 mm	Very high 40

Before and after, from space

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

↔

Before · 27 Jul 2025

After · 18 Aug 2025

Before After

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 · Copernicus

On 5 August 2025 the air beside the fire reached 34 µg/m³ of PM2.5. That day averaged 18: 1.2 times the WHO daily guideline (15).

PM2.5 peak34 µg/m³

Days over the guideline2 days

PM1043 µg/m³

Optical depth0.29

WHO 15

123456

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 · 851Every 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

All fires in United States ›

Frequently asked questions

How long did the Bronco Fire last?: The official perimeter only gives the start date (3 August 2025). The end comes from the heat detections inside the perimeter: it burned until 11 August 2025 (9 days from 3 August 2025), the last day with detections before more than 10 days in a row without any, so it is approximate.
How much area did it burn?: The official perimeter published by United States agencies (MTBS / NIFC) is 7,301 hectares (73.0 km²). Other tallies, such as daily incident reports, may give slightly different figures.
Which counties burned?: The fire only entered Gila (7,328 ha, 0.6 %).
What was the weather like?: During the fire the temperature reached 37.0 °C, humidity dropped to 4 % and gusts hit 47 km/h. The fire danger index (FWI) reached 55, class Extreme.
Where does this data come from?: From the official burnt perimeter of United States agencies (MTBS / NIFC, public domain), NASA FIRMS VIIRS hotspots and the administrative boundaries of United States. 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: 911 · Emergency number and official warnings ›

Satellite cross-check

NASA FIRMS ↗
NIFC · Fire maps ↗

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.

RSS Changes to this page

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.

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What do you think is wrong?

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What really happened?

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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 911.

How we know this

Perimeter: NIFC WFIGS (United States), official.
The official perimeter has no end date: the end is the last day with VIIRS detections inside the perimeter before a gap of more than 10 days (150 days at most), so it is approximate. 851 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.

How we build fire pages: methodology ›

Where this data comes from

The perimeter is official and in the public domain. For past years it comes from MTBS (Monitoring Trends in Burn Severity), run by the U.S. Geological Survey and the USDA Forest Service, which map it on Landsat and Sentinel-2 imagery. For the current and last year it comes from WFIGS at the National Interagency Fire Center (NIFC): incident perimeters mapped by fire crews, aircraft and imagery. Heat detections come from the VIIRS sensors aboard Suomi-NPP and NOAA-20, distributed by NASA FIRMS at 375 m resolution. County boundaries come from geoBoundaries ADM2 (Public Domain). The area per county is computed by WorldFires by crossing the perimeter with those boundaries, so it may differ slightly from official figures.

Where it burned