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Cecil Fire, September 2023 Coconino

Out · last detection 23 Sept 2023, 08:54 UTC

The fire started on 18 September 2023 in Coconino, United States, and satellites saw it burning for 6 days. United States agencies (MTBS / NIFC) mapped an official burnt perimeter of 860 hectares, spread across a single county.

It is the 243th largest in Arizona since 2016 (of 380 with a page). Number 177 in United States in 2023, of 305.

The power measured by the satellite is low (3.5 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…
Burnt area
860ha
official perimeter (MTBS / NIFC)
Duration
≈ 6days
18 Sept 2023 – 23 Sept 2023
Counties hit
1
counties
Started on
18 Sept
2023
Heat detections
5
in a single hotspot: 4 MW
Danger at start
32
High · FWI index
Average daily power
6MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 18 Sept23 Sept
23 Sept 2023

How it evolved, day by day

22 Sept 2023 · 7 MW · 3 23 Sept 2023 · 4 MW · 2
22 Sept 23 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

24°high
71km/h · peak gust
14%lowest humidity

It had gone 4 days without rain (1 mm or more) when it started. Rain came after the fire: 2.6 mm on 1 Oct.

This area had burned before

No earlier perimeters overlap this fire since 2016, when the satellite record begins.

How big is it?

10 km
It burned the equivalent of 0.5% of the area of London (8.6 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. Coconino where it started
    860 ha reached on 22 Sept
    0.0 %

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)
18 Sept 23.6 °C 18 % 52 km/h 0.0 mm High 32
19 Sept 23.2 °C 15 % 44 km/h 0.0 mm High 31
20 Sept 19.9 °C 18 % 59 km/h 0.0 mm High 37
21 Sept 20.4 °C 14 % 71 km/h 0.0 mm Very high 42
22 Sept 21.8 °C 15 % 55 km/h 0.0 mm High 37
23 Sept 17.2 °C 34 % 37 km/h 0.5 mm High 25
24 Sept after 24.3 °C 17 % 24 km/h 0.0 mm High 27
25 Sept after 24.6 °C 13 % 38 km/h 0.0 mm High 33
26 Sept after 25.1 °C 11 % 39 km/h 0.0 mm High 36
27 Sept after 25.0 °C 10 % 44 km/h 0.0 mm Very high 40
28 Sept after 23.7 °C 16 % 49 km/h 0.0 mm Very high 42
29 Sept after 22.9 °C 13 % 53 km/h 0.0 mm Very high 43
30 Sept after 20.5 °C 14 % 78 km/h 0.9 mm Very high 43
1 Oct after 13.5 °C 42 % 72 km/h 2.6 mm Low 10

Before and after, from space

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

Before · 11 Sept 2023
After · 30 Sept 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 16 September 2023 the air beside the fire reached 6 µg/m³ of PM2.5, but no daily average passed the WHO guideline (15).

PM2.5 peak6 µg/m³
Days over the guideline0 days
PM1015 µg/m³
Optical depth0.14
161718192021
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 · 5Every 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 Cecil Fire last?
The official perimeter only gives the start date (18 September 2023). The end comes from the heat detections inside the perimeter: it burned until 23 September 2023 (6 days from 18 September 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 860 hectares (8.6 km²). Other tallies, such as daily incident reports, may give slightly different figures.
Which counties burned?
The fire only entered Coconino (860 ha, 0.0 %).
What was the weather like?
During the fire the temperature reached 23.6 °C, humidity dropped to 14 % and gusts hit 71 km/h. The fire danger index (FWI) reached 42, class Very high.
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. 5 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 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.