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Valentine Fire, August 2023 Gila

Out · last detection 4 Nov 2023, 20:26 UTC

The fire started on 17 August 2023 in Gila, United States, and satellites saw it burning for 80 days. United States agencies (MTBS / NIFC) mapped an official burnt perimeter of 3,917 hectares, spread across a single county.

It is the 86th largest in Arizona since 2016 (of 380 with a page). Number 44 in United States in 2023, of 305.

The power measured by the satellite is low (3.8 MW in the strongest hotspot), more typical of grass or stubble burning, or a slow surface fire, than of a large crown fire.

Compare with…

Suggestions: Fulton · 2016Horton · 2024Highline · 2017Wyrick · 2021

Burnt area
3,917ha
official perimeter (MTBS / NIFC)
Duration
≈ 80days
17 Aug 2023 – 4 Nov 2023
Counties hit
1
counties
Started on
17 Aug
2023
Heat detections
1
in a single hotspot: 4 MW
Danger at start
24
High · FWI index
Average daily power
4MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 17 Aug4 Nov

How it evolved, day by day

4 Nov 2023 · 4 MW · 1

Fire radiative power detected each day, in megawatts, and number of hotspots. The magenta bar marks the peak day.

The weather it burned in

33°high
72km/h · peak gust
10%lowest humidity

It had gone 0 days without rain (1 mm or more) when it started.

This area had burned before

0% of the perimeter overlaps earlier fires recorded since 2016: 16 ha in 2016.

How big is it?

10 km
It burned the equivalent of 2.5% of the area of London (39 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

  1. Gila where it started
    3,952 ha reached on 4 Nov
    0.3 %

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.

People and buildings inside the perimeter

GHSL 2025
Built-up area< 0.1 ha
Residents< 20

Inside 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)
17 Aug 31.5 °C 22 % 30 km/h 0.5 mm High 24
18 Aug 28.7 °C 26 % 35 km/h 0.6 mm High 24
19 Aug 26.9 °C 29 % 49 km/h 0.7 mm High 24
20 Aug 27.2 °C 30 % 70 km/h 1.2 mm High 28
21 Aug 27.0 °C 44 % 45 km/h 4.7 mm Very low 4
22 Aug 28.0 °C 27 % 53 km/h 0.2 mm Moderate 21
23 Aug 27.3 °C 32 % 40 km/h 4.6 mm Very low 5
24 Aug 26.0 °C 41 % 27 km/h 3.2 mm Very low 3
25 Aug 29.4 °C 28 % 21 km/h 0.2 mm Moderate 13
26 Aug 29.4 °C 26 % 18 km/h 0.0 mm Moderate 18
27 Aug 30.0 °C 28 % 23 km/h 0.0 mm Moderate 19
28 Aug 32.5 °C 20 % 24 km/h 0.5 mm High 24
29 Aug 32.9 °C 17 % 23 km/h 0.0 mm High 28
30 Aug 31.4 °C 23 % 32 km/h 0.6 mm High 29
31 Aug 30.0 °C 23 % 35 km/h 2.5 mm Low 11
1 Sept 24.2 °C 38 % 43 km/h 3.6 mm Very low 5
2 Sept 25.2 °C 46 % 32 km/h 1.7 mm Very low 5
3 Sept 26.8 °C 27 % 43 km/h 0.0 mm Moderate 18
4 Sept 25.0 °C 32 % 50 km/h 0.0 mm High 22
5 Sept 27.6 °C 14 % 45 km/h 0.0 mm High 31
6 Sept 28.9 °C 14 % 47 km/h 0.0 mm High 34
7 Sept 29.9 °C 15 % 46 km/h 0.0 mm High 35
8 Sept 31.2 °C 15 % 35 km/h 1.0 mm High 28
9 Sept 31.0 °C 17 % 24 km/h 0.0 mm High 30
10 Sept 29.7 °C 16 % 43 km/h 0.0 mm High 36
11 Sept 26.5 °C 33 % 54 km/h 0.2 mm High 34
12 Sept 19.8 °C 54 % 36 km/h 13.7 mm Very low 1
13 Sept 23.5 °C 48 % 37 km/h 4.0 mm Very low 2
14 Sept 24.4 °C 27 % 32 km/h 0.6 mm Low 7
15 Sept 25.9 °C 18 % 35 km/h 0.0 mm Moderate 17
16 Sept 28.1 °C 15 % 27 km/h 0.0 mm High 24
17 Sept 26.3 °C 29 % 42 km/h 0.0 mm High 24
18 Sept 25.9 °C 18 % 52 km/h 0.0 mm High 29
19 Sept 25.4 °C 15 % 42 km/h 0.0 mm High 28
20 Sept 23.1 °C 22 % 56 km/h 0.1 mm High 32
21 Sept 22.9 °C 13 % 62 km/h 0.0 mm High 37
22 Sept 24.1 °C 11 % 49 km/h 0.0 mm High 35
23 Sept 22.9 °C 18 % 30 km/h 1.1 mm Moderate 17
24 Sept 26.2 °C 21 % 22 km/h 0.0 mm High 23
25 Sept 27.0 °C 12 % 40 km/h 0.0 mm High 33
26 Sept 27.7 °C 12 % 40 km/h 0.0 mm High 36
27 Sept 27.6 °C 12 % 44 km/h 0.0 mm Very high 38
28 Sept 25.9 °C 17 % 50 km/h 0.0 mm Very high 42
29 Sept 25.4 °C 16 % 50 km/h 0.0 mm Very high 43
30 Sept 23.7 °C 13 % 71 km/h 0.0 mm Extreme 53
1 Oct 18.7 °C 27 % 72 km/h 0.0 mm Very high 43
2 Oct 17.6 °C 30 % 55 km/h 0.0 mm High 33
3 Oct 20.4 °C 22 % 34 km/h 0.0 mm High 26
4 Oct 22.7 °C 17 % 37 km/h 0.0 mm High 31
5 Oct 26.2 °C 13 % 30 km/h 0.0 mm High 37
6 Oct 27.0 °C 14 % 34 km/h 0.0 mm High 35
7 Oct 24.9 °C 24 % 44 km/h 1.0 mm High 27
8 Oct 24.7 °C 24 % 36 km/h 2.7 mm Low 10
9 Oct 23.8 °C 24 % 38 km/h 0.2 mm Moderate 21
10 Oct 22.6 °C 22 % 48 km/h 0.0 mm High 31
11 Oct 20.8 °C 28 % 72 km/h 0.0 mm Very high 39
12 Oct 18.7 °C 12 % 49 km/h 0.0 mm High 36
13 Oct 20.3 °C 16 % 34 km/h 0.0 mm High 31
14 Oct 22.8 °C 20 % 31 km/h 0.0 mm High 31
15 Oct 26.1 °C 12 % 30 km/h 0.0 mm High 36
16 Oct 26.5 °C 17 % 26 km/h 0.0 mm High 35
17 Oct 25.4 °C 20 % 38 km/h 0.1 mm High 37
18 Oct 26.8 °C 14 % 22 km/h 0.0 mm High 34
19 Oct 27.9 °C 11 % 24 km/h 0.0 mm Very high 38
20 Oct 27.4 °C 11 % 28 km/h 0.0 mm Very high 39
21 Oct 24.9 °C 15 % 44 km/h 0.0 mm Very high 45
22 Oct 23.9 °C 17 % 41 km/h 0.0 mm Very high 42
23 Oct 19.9 °C 25 % 53 km/h 0.0 mm Very high 41
24 Oct 17.5 °C 37 % 34 km/h 0.9 mm Moderate 17
25 Oct 16.8 °C 40 % 41 km/h 0.0 mm High 21
26 Oct 16.7 °C 40 % 47 km/h 0.0 mm High 23
27 Oct 18.3 °C 32 % 43 km/h 0.0 mm High 25
28 Oct 16.3 °C 33 % 58 km/h 0.0 mm High 29
29 Oct 12.7 °C 22 % 49 km/h 0.0 mm High 30
30 Oct 12.8 °C 21 % 39 km/h 0.0 mm High 29
31 Oct 15.1 °C 13 % 34 km/h 0.0 mm High 32
1 Nov 17.6 °C 11 % 27 km/h 0.0 mm High 32
2 Nov 20.2 °C 12 % 24 km/h 0.0 mm High 33
3 Nov 21.4 °C 10 % 23 km/h 0.0 mm High 35
4 Nov 22.7 °C 11 % 22 km/h 0.0 mm High 36
5 Nov after 21.8 °C 20 % 48 km/h 0.0 mm Very high 43
6 Nov after 21.0 °C 19 % 54 km/h 0.0 mm Very high 45
7 Nov after 19.7 °C 19 % 58 km/h 0.0 mm Very high 47
8 Nov after 15.5 °C 17 % 39 km/h 0.0 mm Very high 40
9 Nov after 11.8 °C 22 % 47 km/h 0.0 mm High 37
10 Nov after 13.2 °C 23 % 28 km/h 0.0 mm High 32
11 Nov after 14.3 °C 23 % 32 km/h 0.0 mm High 30
12 Nov after 17.1 °C 14 % 36 km/h 0.0 mm High 33
13 Nov after 17.2 °C 26 % 36 km/h 0.0 mm High 32
14 Nov after 18.7 °C 25 % 29 km/h 0.0 mm High 30

Before and after, from space

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

Before · 10 Aug 2023
After · 11 Nov 2023

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 20 August 2023 the air beside the fire reached 12 µg/m³ of PM2.5, but no daily average passed the WHO guideline (15).

PM2.5 peak12 µg/m³
Days over the guideline0 days
PM1018 µg/m³
Optical depth0.24
151617181920
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 · 1Every 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 United States ›

Frequently asked questions

How long did the Valentine Fire last?
The official perimeter only gives the start date (17 August 2023). The end comes from the heat detections inside the perimeter: it burned until 4 November 2023 (80 days from 17 August 2023), 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 3,917 hectares (39.2 km²). Other tallies, such as daily incident reports, may give slightly different figures.
Which counties burned?
The fire only entered Gila (3,952 ha, 0.3 %).
What was the weather like?
During the fire the temperature reached 32.9 °C, humidity dropped to 10 % and gusts hit 72 km/h. The fire danger index (FWI) reached 53, 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

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.

Report an error
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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: MTBS (US Geological Survey and US Forest Service), 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. One Suomi-NPP VIIRS detection 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.

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.